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The way PC-based instrumentation should be
DI-900MB Series
Modbus/RS485 Network I/O Modules
Model DI-932MB
Dual RTD Input/Digital Ouput
Model DI-934MB
Quad RTD Input/Digital Output
User’s Manual
Copyright © 2003 by DATAQ Instruments, Inc. The Information contained herein is the exclusive property of DATAQ
Instruments, Inc., except as otherwise indicated and shall not be reproduced, transmitted, transcribed, stored in a
retrieval system, or translated into any human or computer language, in any form or by any means, electronic,
mechanical, magnetic, optical, chemical, manual, or otherwise without expressed written authorization from the company. The distribution of this material outside the company may occur only as authorized by the company in writing.
DATAQ Instruments' hardware and software products are not designed to be used in the diagnosis and treatment of
humans, nor are they to be used as critical components in any life-support systems whose failure to perform can reasonably be expected to cause significant injury to humans.
Windows 95/98 & NT are registered trademarks of Microsoft Corporation. Modbus is a registered trademark of
Modicon, Inc.
241 Springside Dr., Suite #200
Akron, Ohio 44333 U.S.A.
Telephone: 330-668-1444
Fax: 330-666-5434
Designed and manufactured in the
United States of America
Warranty and Service Policy
Product Warranty
DATAQ Instruments, Inc., warrants the instruments described in this manual to be free from defects in materials and
factory workmanship to the original buyer. This warranty is contingent upon proper use of the equipment, and does
not cover equipment that has been modified or has been subjected to abusive physical or electrical stresses. DATAQ
Instruments, Inc., agrees to repair or replace, at its sole discretion, any instrument that fails to perform as specified
within 18 months after date of the original shipment from the factory, or 12 months after the date of installation,
whichever date comes first.
DATAQ Instruments, Inc., reserves the right to make substitutions and modifications in the specifications of equipment that do not materially or adversely affect the performance of the equipment.
New equipment may be returned within 30 days of shipment with prior factory approval and upon the assignment of
a Returned Material Authorization number, RMA number, by DATAQ Instruments, Inc. This number must be clearly
shown on the return package(s). RMA numbers are valid for 30 days from date of issue. New items in factory sealed
containers which are less than thirty days old after shipment may be returned for credit, less a minimum restocking
and testing charge of twenty percent of the list price upon factory approval only, provided the customer pays all shipping and handling charges. Specially ordered, or modified goods, or goods which have been used or have been
unpacked from the factory-sealed containers, or goods which have been shipped more than thirty days prior are not
returnable.
The information contained in this manual is subject to change without notice. DATAQ Instruments, Inc., makes no
warranty of any kind with regard to this material, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose. Further, DATAQ Instruments, Inc., assumes no responsibility for any
errors that may appear in this manual and makes no commitment to update, or keep current, the information contained
in this manual.
Service Policy
Units within the warranty period returned for repair, test, and recalibration are serviced at no charge in accordance
with the terms of the warranty policy. The Customer pays all transportation and other charges to the factory.
Units out of warranty returned for repair, test, and/or recalibration are handled on a time and material basis. If
requested, or if costs exceed 50% of current list price, DATAQ Instruments, Inc., advises the customer prior to making
the repairs. Such repairs are performed at the customer’s expense. Typical test, recalibration, and repairs are 25% of
the instrument’s current list price. Transportation charges both ways are at the customer’s expense.
Please be sure all returns are shipped with the following information included:
1.
“Returned Material Authorization,” RMA number, clearly shown on each package. Please call DATAQ Instruments, Inc., at 330-668-1444 to obtain your RMA number.
2.
Your company Name with Billing and Shipping Addresses.
3.
A complete description of your problem, or re-calibration data.
4.
The contact person at your company, with their telephone and facsimile numbers.
5.
Non-Warranty returns additionally need your Purchase Order Number.
Please pack your returned instruments in their original shipping cartons, or in equivalent strong protective shipping
cartons.
Service and Repair Assistance
This module contains solid-state components and requires no maintenance, except for periodic cleaning and transmitter configuration parameter (zero, full-scale, setpoint, deadband, etc) verification. Since Surface Mount Technology
(SMT) boards are generally difficult to repair, it is highly recommended that a non-functioning module be returned to
DATAQ Instruments Inc., for repair. The board can be damaged unless special SMT repair and service tools are used.
Further, DATAQ Instruments, Inc., has automated test equipment that thoroughly checks and calibrates the performance of each module. Please contact DATAQ Instruments, Inc., for complete details on how to obtain service parts
and repair..
CAUTION: Risk of Electric Shock - More than one disconnect switch may be
required to de-energize the equipment before servicing.
Preliminary Service Procedure
Before beginning repair, be sure that all installation and configuration procedures have been followed. Make sure
that the correct baud rate is selected for the RS232-to-RS485 converter employed. The unit routinely performs internal diagnostics following power-up or reset. During this period, the green “Run” LED flashes.
If the diagnostics complete successfully, the “Run” LED will stop flashing after two seconds and remain ON. This
indicates that the unit is operating normally. If the “Run” LED continues to flash, then this is indicative of a problem.
In this case, use the Modbus Configuration Software to reconfigure the module and this will usually cure the problem.
If the diagnostics continue to indicate a problem (a continuously flashing green LED), or if other evidence points to a
problem with the unit, an effective and convenient fault diagnosis method is to exchange the questionable module
with a known good unit. DATAQ Instruments' Application Engineers can provide further technical assistance if
required. When needed, complete repair services are available from DATAQ Instruments, Inc.
Safety Summary
!
Means “Caution, refer to this manual for additional information.”
IMPORTANT SAFETY CONSIDERATIONS
It is very important for the user to consider the possible adverse effects of power, wiring, component, sensor,
or software failures in designing any type of control or monitoring system. This is especially important
where economic property loss or human life is involved. It is important that the user employ satisfactory
overall system design. It is agreed between the Buyer and DATAQ Instruments, Inc., that this is the Buyer’s
responsibility.
Model 932MB/934MB Modbus/RS485 Network I/O Modules
Table of Contents
Warranty and Service Policy ................................................................................................................
1. Introduction ........................................................................................................................................
Description .........................................................................................................................................
Key DI-932MB/DI-934MB Module Features: ..................................................................................
2. Specifications ......................................................................................................................................
General ...............................................................................................................................................
Model Number Definition .................................................................................................................
Analog Input Specifications ..............................................................................................................
Digital Output Specifications ............................................................................................................
Enclosure/Physical Specifications .....................................................................................................
Approvals (-xxx0) ..............................................................................................................................
Environmental Specifications ............................................................................................................
Communication Interface Specifications ...........................................................................................
Configuration and Controls ...............................................................................................................
Software Configuration .....................................................................................................................
Other Modbus Configuration Software Capabilities .........................................................................
3. Getting Started ...................................................................................................................................
Unpacking and Inspection .................................................................................................................
Module Installation ............................................................................................................................
Default Mode Switch ..................................................................................................................
Mounting .....................................................................................................................................
Electrical Connections ................................................................................................................
Software Installation—Using Setup.exe ............................................................................................
4. Module Configuration ...................................................................................................................
Register Map ......................................................................................................................................
5. An Introduction to Modbus ...............................................................................................................
Remote Terminal Unit (RTU) Mode .................................................................................................
Modbus Message Framing .................................................................................................................
How Characters Are Transmitted Serially .........................................................................................
Modbus Addresses .............................................................................................................................
Modbus Functions .............................................................................................................................
Read Coil Status (01) ..................................................................................................................
Read Holding Registers (03) .......................................................................................................
Read Input Registers (04) ...........................................................................................................
Force Single Coil (05) .................................................................................................................
Preset Single Register (06) ..........................................................................................................
Force Multiple Coils (15) ............................................................................................................
Preset Multiple Registers (16) .....................................................................................................
Report Slave ID (17) ...................................................................................................................
Reset Slave (08) ..........................................................................................................................
Modbus Data Field ............................................................................................................................
Supported Data Types .......................................................................................................................
Modbus Error Checking Fields ..........................................................................................................
Parity Checking .................................................................................................................................
CRC Error Checking .........................................................................................................................
Table of Contents
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Model 932MB/934MB Modbus/RS485 Network I/O Modules
Modbus Exceptions ...........................................................................................................................
6. Module Software Configuration .......................................................................................................
Before You Begin ..............................................................................................................................
Starting The Program .........................................................................................................................
File ...............................................................................................................................................
Module ........................................................................................................................................
Settings ........................................................................................................................................
Help .............................................................................................................................................
Creating A Configuration File ...........................................................................................................
Module ........................................................................................................................................
Alarm Configuration ..........................................................................................................................
Alarm Config Field Descriptions ................................................................................................
Limit Alarm (Each Input) ............................................................................................................
Writing Your Configuration ........................................................................................................
Testing Your Configuration ...............................................................................................................
Test Operation .............................................................................................................................
Print Your Configuration ............................................................................................................
Saving Your Configuration .........................................................................................................
Module Calibration ............................................................................................................................
Module Input Calibration ............................................................................................................
7. Block Diagrams and Schematics .......................................................................................................
Theory of Operation ..........................................................................................................................
Simplified Schematic (4501-893) ......................................................................................................
Functional Block Diagram (4501-894) ..............................................................................................
Network Connections (4501-805) .....................................................................................................
Electrical Connections (4501-895) ....................................................................................................
Interposing Relay Conn. & Contact Pro. (4501-896) ........................................................................
Enclosure Dimensions (4501-897) ....................................................................................................
8. Accessories ..........................................................................................................................................
Series DI-900MB Software Interface Package (Model 100969) .......................................................
DI-900MB Configuration & Control Software ...........................................................................
RS-232 to RS-485 Serial Adapter ...............................................................................................
Interface Cable ............................................................................................................................
Isolated Signal Converter (Models 100974 and 100975) ..................................................................
Isolated Network Repeater (Models 100977 and 100978) ................................................................
Table of Contents
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Model 932MB/934MB Modbus/RS485 Network I/O Modules
1. Introduction
These instructions cover the hardware functionality of the transmitter models listed in the Table below. Supplementary sheets are attached for units with special options or features.
Models Covered in This Manual
Series/Input Type
3
DI-932MB
DI-934MB3
-Options/Output/Enclosure/ Approvals1
-0900
-0900
-Factory Configuration2
-C
-C
Notes:
1. Agency approvals include CE, UL Listed, and cUL Listed.
2.
Include the “-C” suffix to specify factory configuration option. Otherwise, no suffix is required for standard configuration.
3.
The DI-932MB model supports two RTD channels, while the DI-934MB model supports four RTD channels.
Description
The DI-900MB family is a group of process I/O modules and accessories for Modbus/RS485 network I/O applications. The Model DI-932MB will condition up to two RTD inputs, while the DI-934MB will condition up to four
RTD inputs. Both models provide an isolated RS485 network I/O path utilizing the industry standard Modbus protocol, and include isolated control outputs for high/low limit alarm support, or for simple ON/OFF control of external
devices. These modules contain an advanced technology microcontroller with integrated downloadable flash memory and EEPROM for non-volatile program, configuration, calibration, and parameter data storage. Units are fully
reconfigurable via our user-friendly Windows® Configuration Program and the RS485 interface. Once configured,
these modules may operate as an active RS485 network slave connected to other modules and a host computer.
These modules provide two (DI-932MB), or four (DI-934MB) inputs for RTD signals, connected in 2-wire or 3-wire
format. Sensor excitation, linearization, lead-wire compensation, and upscale/ downscale lead break detection are
included. The module uses a high resolution, low noise, Sigma-Delta Analog to Digital Converter (Σ−∆ ADC) to
accurately convert the input signals into digitized values. Inputs also include high/low alarm functionality with solidstate relay output switches. These output channels include a yellow LED on the front of the module that provides
visual indication of its on/off state and/or alarm condition. Additionally, a green “Run” and yellow “Status” LED
provides local feedback of operating mode, system diagnostics, watchdog timeout, and module status.
All DI-900MB modules are designed to withstand harsh industrial environments. They feature RFI, EMI, ESD, EFT,
and surge protection, plus low temperature drift, wide ambient temperature operation, and isolation between signal I/
O, power, and the network. They also have low radiated emissions per CE requirements. As wide-range DC-powered devices, these units may be powered from DC power networks incorporating battery backup, or from common
24VAC power. Since the input supply is diode-bridge coupled, the unit may be connected to redundant power supplies, or several units may safely share a single DC supply. All Modbus units are DIN-rail mounted and removable
terminal blocks facilitate ease of installation and replacement, without having to remove wiring. Transmitter power,
network, and relay output wiring are inserted at one side of the unit, while input wiring is inserted at the other side.
Plug-in connectors are an industry standard screw clamp type that accept a wide range of wire sizes.
Flexible transmitter functionality, network reprogrammability, mixed signal I/O, alarm support, and a network interface, all combine in a single package to make this instrument extremely powerful and useful over a broad range of
applications. Further, the safe, compact, rugged, reconfigurable, and reliable design of this transmitter makes it an
ideal choice for control room or field applications. Custom module configurations are also possible (please consult
the factory).
Introduction
1
Model 932MB/934MB Modbus/RS485 Network I/O Modules
Key DI-932MB/DI-934MB Module Features:
•
Agency Approvals - CE, UL, & cUL Listings.
•
Easy Windows® Configuration - Fully reconfigurable via our user-friendly Windows® Series DI-900MB Configuration Program.
•
RS485/Modbus Network Interface - This proven high speed interface is highly immune to noise, can operate
over long distances, and allows a large number of modules to be networked together. The unit communicates
using the industry-standard Modbus command/response protocol.
•
Nonvolatile Reprogrammable Memory - An advanced technology microcontroller with integrated, non-volatile, downloadable flash memory and EEPROM allows the functionality of this device to be reliably reprogrammed thousands of times.
•
Fully Isolated - The input, outputs, network, and power are all isolated from each other for safety and increased
noise immunity.
•
Flexible Dual or Quad RTD Inputs - Accepts two or four channels of input for Platinum (Pt), Copper (Cu), and
Nickel (Ni) RTD types, or simple resistance. Linearization, excitation, and lead break detection are included.
•
Dual/Quad Discrete SSR or Alarm Outputs - High voltage, high current, solid-state relays provide for direct
control, or alarm control of external devices. Output relays may be activated independently, via watchdog timeout, or under alarm control, in both failsafe and non-failsafe modes.
•
Self-Diagnostics - Built-in routines operate upon power-up for reliable service, easy maintenance, and convenient troubleshooting. In addition, a hardware watchdog timer is built into the microcontroller that causes it to
initiate a self reset if the controller ever “locks up” or fails to return from an operation in a timely manner.
•
High-Speed Data Rates - Supports RS485 communication rates up to 115K baud.
•
Wide Ambient Operation - The unit is designed for reliable operation over a wide ambient temperature range.
•
Ratiometric Differential RTD Sampling - The RTD signal is sampled differentially using a ratiometric conversion method that increases accuracy.
•
Wide-Range DC-Power or 24VAC Power - This device receives power over a wide supply range and the
power terminals are diode-bridge coupled, making this transmitter useful for systems with redundant supplies,
and/or battery back-up. Additionally, the power terminals are not polarized.
•
Watchdog Timer - An I/O watchdog timer function is included and may be configured for timeout periods up to
65534 seconds (18.2 hours). This timer will timeout if a read or write operation to any I/O channel does not
occur over the configured time period. Optionally, outputs may be automatically set to user-defined states following timeout. Watchdog control of the output relay has a higher priority than alarm control and direct control.
•
Hardened For Harsh Environments - The unit will operate reliably in harsh industrial environments and
includes protection from RFI, EMI, ESD, EFT, and surges, plus low radiated emissions per CE requirements.
•
Convenient Mounting, Removal, & Replacement - The DIN-rail mount and plug-in type terminal blocks make
module installation, removal, and replacement easy.
•
High-Resolution Precise A/D Conversion - Transmitters include high-resolution, low noise, Sigma-Delta Analog to Digital Converters (Σ−∆ ADC) for high accuracy & reliability.
•
LED Indicators - A green LED indicates power. A yellow status LED will turn on if an input signal is out of
calibrated range or a lead break has occurred, or will flash if the unit is placed in the default communication
mode. It will also flash rapidly upon watchdog timeout. Another yellow output LED indicates the ON/OFF state
of the associated output relay.
•
Default Communication Mode - A push-button switch is provided to set the module to a default set of communication parameters for baud rate, module address, parity, and number of stop bits. This provides a convenient
way of establishing communication with the module when its internal settings are unknown.
•
Automatic Self-Calibration - Built-in self-calibration helps correct for temperature drift of the input circuit
every 60 seconds.
Introduction
2
Model 932MB/934MB Modbus/RS485 Network I/O Modules
•
Upscale Or Downscale Break Detection - Inputs may be configured to go upscale or downscale upon lead
breakage.
•
Alarm Functionality - Alarm limit checking is always active for the module. High and/or low limit levels, plus
deadband may be configured at each input. Optionally, failsafe or non-failsafe alarm outputs may be enabled for
each limit. Alarm control has priority over direct control of an output relay.
•
Configurable Setpoint With Deadband - Includes programmable deadband to help eliminate output relay
switch “chatter.”
Introduction
3
Model 932MB/934MB Modbus/RS485 Network I/O Modules
2. Specifications
General
The Model DI-932MB and DI-934MB modules are DC-powered or 24VAC powered network transmitters which
condition two (DI-932MB) or four (DI-934MB) channels of RTD or resistance input, and provide an isolated
RS485/Modbus network interface, plus four solid-state relay outputs. Isolation is supplied between inputs (as a
group), the network, power, and the outputs (as a group). Outputs may be operated independently, or as alarm outputs for ON/OFF control of external devices. This network transmitter is DIN-rail mounted.
Units can be easily configured and calibrated with the user-friendly Windows® Configuration Program. Optionally,
you may use your own software as long as you adhere to the Modbus command/response format for supported commands. A push button on the module allows you to set the module address, baud rate, and parity to Default Mode
values if the internal settings are unknown. Non-volatile re-programmable memory in the module stores calibration
and configuration information.
Model Number Definition
DI-932MB-0900: Transmits/isolates two RTD or resistance inputs.
DI-934MB-0900: Transmits/isolates four RTD or resistance inputs.
Input transmitters are color coded with a white label. The prefix “9” refers to the Series 900. The “MB” suffix
denotes ModBus. The four digit suffix of this model number represents the following options, respectively: 0 = No
Options; 9 = Output: RS485/Modbus; 0 = Enclosure: DIN rail mount; 0 = Approvals: CE, UL Listed, and cUL
Listed (Pending).
Analog Input Specifications
The unit must be wired and configured for the intended input type and range (see Module Installation for details).
The same input type and break detect direction is configured across all input channels. The following paragraphs
summarize this model's input types, ranges, and applicable specifications.
RTD: User configured to one of four RTD types, or as a simple resistance input as
noted in Table: RTD Types, Ranges, and Accuracy below. The module supports 2 or 3-wire connection types and provides sensor excitation, linearization,
lead-wire compensation (3-wire mode), and sensor lead break detection.
Input Reference Test Conditions: Pt RTD 0°C to 100°C, Ni RTD 0°C to 50°C, Cu RTD 0°C to 250°C; Ambient =
25°C; Power Supply = 24V DC.
Input Configuration: Two-wire or three-wire only.
Excitation Current: 1mA DC typical, all types.
Linearization: Better than ±0.25°C, typical.
Lead-Wire Compensation: Applies to 3-wire RTD with lead wires of equal size and length. The maximum
possible resistance including lead wires is 506Ω. Thus, the maximum lead
resistance is approximately 25Ω per lead (Pt), 15Ω per lead (Ni), 10Ω per lead
(Cu), 3Ω per lead (500Ω resistance).
Lead Resistance Effect: 3.5°C per Ω of unbalance, typical (Pt), 1.4°C per Ω of unbalance, typical (Ni),
25.5°C per Ω of unbalance, typical (Cu).
Specifications
5
Model 932MB/934MB Modbus/RS485 Network I/O Modules
Break Detection: Sensor failure (open) or lead breakage can provide upscale or downscale indication for all channels. This applies to each lead individually, or all leads
together. Note that this will also trigger an out-of-range indication (module
Status LED constant ON).
IMPORTANT (0-500 ohm inputs The maximum input resistance including lead wires is about 506Ω. If break
w/ break detection): detection is set downscale and your input resistance is greater than 506Ω (saturated), this will trigger break detection and the input reading will be sent downscale for the over-range input resistance without actual lead breakage.
Likewise, upscale break is indistinguishable from an over-range input resistance greater than 506Ω.
RTD Types, Ranges, and Accuracy
RTD Type
α Alpha
Pt 100Ω
1.3850
Pt 100Ω
1.3911
Ni 120Ω
1.6720
Cu 10Ω
1.4272
Resistance (Linear)
1.000
°C Range
-200 to +850°C
-200 to +850°C
-80 to +320°C
-200 to +260°C
0 to 500Ω
Typical Accuracy
±0.25°C
±0.25°C
±0.25°C
±1.25°C
±0.05Ω
Notes:
1.
Alpha (α) is used to identify the particular RTD curve. The value of alpha is derived by dividing the resistance
of the sensor at 100°C by the resistance at 0°C (α = R100°C/R0°C). For Pt 100Ω, this is 138.5Ω/100.0Ω, or 1.385
(also shown as 0.00385Ω/Ω/°C).
General Input Specifications
Accuracy: Accuracy is better than ±0.05% of span, typical for nominal input ranges (see
Table: RTD Types, Ranges, and Accuracy, above). This includes the effects of
repeatability, terminal point conformity, and linearization, but does not include
sensor error.
Accuracy Versus Temperature: Better than ±0.005% of input span per °C (±50ppm/ºC or ±1uV/°C, whichever
is greater).
Resolution: 0.005% or 1 part in 20000. See Table below.
Effective Resolution Per Applicable Range
Range
Resolution
10Ω Cu (α=1.4272)
0.2°C (0.36°F)
Pt (α=1.3850)
0.1°C (0.18°F)
Pt (α=1.3911)
0.1°C (0.18°F)
Ni (α=1.6720)
0.1°C (0.18°F)
0 to 500Ω
7.8125mΩ
Input Filter: Normal mode filtering, plus digital filtering, optimized and fixed per input
range within the Σ−∆ ADC.
Input Filter Bandwidth: -3dB at 3Hz, typical.
Noise Rejection (Normal Mode): Better than 40dB @ 60Hz, typical with 100Ω input unbalance.
Noise Rejection (Common Mode): Better than 130dB @ 60Hz, typical with 100Ω input unbalance (10Ω unbalance for Cu RTD).
Specifications
6
Model 932MB/934MB Modbus/RS485 Network I/O Modules
Analog to Digital Converter (A/D): A 16-bit Σ−∆ converter, Analog Devices AD7714AR-5. A/D reference is
1020Ω (1.02V at 1mA excitation). The differential input is sampled ratiometric to the reference.
Input Bias current: 1mA DC excitation current.
Input Conversion Rate: Maximum 1.5625 conversions per channel per second (80ms/sample * 2 samples/ conversion * 4 channels = 640ms per scan).
Digital Output Specifications
Isolated Solid-State Relays (one per input channel) operate as discrete outputs, alarm outputs, or watchdog timeout
outputs. Alarm control of the output state has a higher priority than direct control. Watchdog timeout control (timeout state) will have the highest priority when enabled. Disable alarm outputs if direct control is desired. Outputs are
turned OFF following a software or power-on reset.
Output Channel: Solid-State Relay (SSR), one Form A switch (SPST-NO) per input channel.
Outputs share a common return connection at the RTN terminals. Observe
proper polarity. To control higher voltages and/or currents, or for controlling
AC, an interposing relay may be used (see Drawing Electrical Connections
(4501-895)).
Output “OFF” Voltage Range: 0 to 48V DC.
Output “OFF” Leakage Current: 1uA typical at 48VDC.
Output “ON” Current Range: 0 to 1A DC (up to 40°C) continuous, for each output switch with one RTN termination per each output pair.
Derate “ON” Current Above 40°C: 10mA per °C.
Output “ON” Resistance: 0.4Ω Maximum.
Output “ON” Voltage: 0.4V DC Maximum at 1A DC.
Output Response Time: Digital Outputs: 5ms, typical, measured from receipt of force coil command to
switch state transfer. Effective time will vary with output load. Alarm outputs
will change states for a step change in the input from one side of the alarm level
to the other within 650ms (varies between 180ms and 630ms typical).
Enclosure/Physical Specifications
See Enclosure Dimensions Drawing 4501-897. Units are packaged in a general purpose plastic enclosure that is
DIN rail mountable for flexible, high density (approximately 1" wide per unit) mounting.
Dimensions: 1.05 inches wide, 4.68 inches high, 4.35 inches deep (see Drawing Enclosure
Dimensions (4501-897)).
DIN Rail Mounting (-xx0x): Type EN50022; “T” rail (35mm).
Connectors: Removable plug-in type terminal blocks rated up to 15A/300V for stranded or
solid wire from 12-24 AWG. For supply connections, use No. 14 AWG copper
wires rated for at least 75°C.
Case Material: Self-extinguishing NYLON type 6.6 polyamide thermoplastic UL94 V-2, color
beige; general purpose NEMA Type 1 enclosure.
Printed Circuit Boards: Military grade FR-4 epoxy glass.
Shipping Weight: 1 pound (0.45 Kg) packed.
Specifications
7
Model 932MB/934MB Modbus/RS485 Network I/O Modules
Approvals (-xxx0)
0: Agency Approvals - CE, UL Listed, and cUL Listed. UL3121 First Edition,
CSA C22.2 No. 1010.1-92, Low Voltage Directive (72/23/EEC), EMC (89/
336/EEC) Directives. Product approval is limited to general safety requirements of the above standards.
Warning: Product is NOT approved for hazardous locations.
Environmental Specifications
Operating Temperature: -25°C to +70°C (-13°F to +158°F).
Storage Temperature: -40°C to +85°C (-40°F to +185°F).
Relative Humidity: 5 to 95%, non-condensing.
Power Requirements: 10V to 36V DC SELV (Safety Extra Low Voltage), or 22-26 VAC. The power
terminals are diode-bridge coupled and are not polarized. Current draw is a
function of supply voltage (see Supply Current Tables below). Currents shown
assume all outputs are ON.
Caution: Do not exceed 36VDC peak, to avoid damage to the module.
DI-932MB Supply Current
Supply
DI-932MB Current Draw
10V
90mA Typical, 105mA Maximum
12V
72mA Typical, 80mA Maximum
15V
58mA Typical, 65mA Maximum
24V
38mA Typical, 42mA Maximum
36V
29mA Typical, 34mA Maximum
24VAC
68mArms Typical, 76mArms Maximum
DI-934MB Supply Current
Supply
DI-934MB Current Draw
10V
120mA Typical, 135mA Maximum
12V
97mA Typical, 110mA Maximum
15V
76mA Typical, 85mA Maximum
24V
50mA Typical, 60mA Maximum
36V
38mA Typical, 42mA Maximum
24VAC
89mArms Typical, 100mArms Maximum
Power Supply Effect
Volts: Less than ±0.001% of output span change per volt for rated power supply variations.
60/120 Hz Ripple: Less than 0.01% of output span per volt peak-to-peak of power supply ripple.
Specifications
8
Model 932MB/934MB Modbus/RS485 Network I/O Modules
Isolation: Inputs (as a group), network, power, and digital outputs (as a group) are isolated from each other for common-mode voltages up to 250VAC, or 354V DC
off DC power ground, on a continuous basis (will withstand 1500VAC dielectric strength test for one minute without breakdown). This complies with test
requirements of ANSI/ISA-82.01-1988 for the voltage rating specified. Note
that inputs and outputs are not isolated channel-to-channel. However, inputs
do provide some common mode noise isolation channel-to-channel for small
voltages up to 4V DC.
Installation Category: Designed to operate in an Installation Category (Overvoltage Category) II
environment per IEC 1010-1 (1990).
Electromagnetic Interference No alarm trips will occur beyond ±0.25% of input span from setpoint, and no
Immunity (EMI): output shifts will occur beyond ±0.25% of span, while under the influence of
EMI from switching solenoids, commutator motors, and drill motors.
Electromagnetic Compatibility Immunity Per European Norm
EN50082-1
Electrostatic Discharge (ESD) 4KV direct contact and 8KV air discharge to the enclosure port per EN61000Immunity: 4-2.
Radiated Field Immunity (RFI): 3V/M, 80 to 1000MHz AM and 900MHz keyed carrier, per EN61000-4-3 and
ENV50204.
Electrical Fast Transient Immunity 0.5KV to power and signal I/O per EN61000-4-4.
(EFT):
Conducted RF Immunity (CRFI): 3Vrms, 150KHz to 80MHz, per EN61000-4-6.
Surge Immunity: 0.5KV per EN61000-4-5.
Emissions Per European Norm
EN50081-1
Radiated Frequency Emissions: 30 to 1000MHz per EN55022 Class B.
Communication Interface Specifications
These units contain an isolated RS485 communication port for the transmission of data.
Interface Standard: RS-485. Communication with this module is made over a 3-wire cable (D, Dbar, and Common).
Command/Response Protocol: Standard Modbus RTU protocol implemented as defined under “Modicon
Modbus Reference Guide” PI-MBUS-300 Rev J (reference www.public.modicon.com, search keyword PI-MBUS-300 to obtain technical publication). See
MODULE CONFIGURATION for a review of Modbus & commands.
Baud Rate: Can be programmed for 2400, 4800, 9600 (Default Mode rate), 14400, 19200,
28800, 38400, 57600, 76800, or 115200 bits per second.
Duplex: Half Duplex only.
Parity: Odd, Even, or None (Default Mode). The absence of parity is equivalent to 2
stop bits.
Stop Bits: One for Even or Odd parity, two for no parity.
Specifications
9
Model 932MB/934MB Modbus/RS485 Network I/O Modules
Response Delay: The minimum communication turnaround delay that a module will wait before
it sends its response to a message from the host. As a minimum value, it must
be set greater than the inherent delay already present in order to be effective. It
can be set from 0-65500 ticks, with 1 tick equivalent to 1.085us. Some signal
converters or host/ software systems cannot accept an immediate response
from the slave without additional delay. Try increasing this delay if you experience communication problems.
Module Address: Can be set from 0-247 (01H-F7H). The Default Mode address is 247 (F7H).
Network Capacity: The Module has multi-drop capability for up to 31 modules, plus host, without
use of an RS485 repeater. If a signal repeater is used for every 31 nodes, up to
247 modules may be networked, plus a host computer.
Communication Distance: Up to 4000 feet without a repeater. Distance can be extended with the use of a
signal repeater.
Default Communication Mode In this mode, the module address is set to 247, the baud rate is set to 9600bps,
Parameters: the parity is set to none (2 stop bits) by pressing the DFT push-button on the
front of the module until the yellow Status LED flashes ON/OFF. This allows
communication with a module when its internal settings are unknown. Exit the
Default Mode by pressing this button until the Status LED is NOT flashing
(constant ON or OFF), or by issuing a software or power-on reset. Note that
new communication parameters for module address, baud rate, and parity take
effect outside of Default Mode after a software or power-on reset.
Watchdog Timer: A hardware watchdog timer is built into the microcontroller that causes it to
self-reset if the controller ever fails to return from an operation or “locks up.”
Additionally, an I/O watchdog timer function is included that may be set for
timeout periods up to 65534 seconds (18.2 hours). The I/O watchdog timer
will cause the status LED to blink rapidly, set a bit in the Module Status Register, and optionally program the digital outputs to a pre-defined state upon timeout. The I/O watchdog timer is reinitiated via a read or write to any input/
output channel. Clearing a timeout condition will not automatically restore the
outputs to their initial state. Outputs have to be driven manually or under alarm
control.
Supported Modbus Commands: The command & response protocol for communicating with this module
adheres to the Modbus/RTU standard for the following Modbus Functions (the
register reference addresses that the function operates on are also indicated).
Refer to MODULE CONFIGURATION for detailed information on each of
these functions:
Code
01 (01H)
03 (03H)
04 (04H)
05 (05H)
06 (06H)
08 (08H)
15 (0FH)
16 (10H)
17 (11H)
Function
Read Coil (Output) Status
Read Holding Registers
Read Input Registers
Force Single Coil (Output)
Preset Single Register
Reset Slave
Force Multiple Coils (Outputs)
Preset Multiple Registers
Report Slave ID
Configuration and Controls
Specifications
10
Reference
0xxxx
4xxxx
3xxxx
0xxxx
4xxxx
Hidden
0xxxx
4xxxx
Hidden
Model 932MB/934MB Modbus/RS485 Network I/O Modules
Module Push Button (See Dwg. Default (DFT) - Push to engage or disengage the default communication mode
4501-897 For Location): with baud rate set to 9600bps, module address set to 247, and no parity
selected. The Status LED will flash ON/OFF when the module is in the default
mode. A module will leave the default mode following a software or power-on
reset (Status LED will be OFF or constant ON).
LED Indicators: Run (Green) - Constant ON indicates power is applied and unit is operating
normally. Flashing ON/OFF indicates unit is performing diagnostics (first two
seconds following power-up), or has failed diagnostics (after a few seconds).
Status (Yellow) - Flashing LED indicates the module is in the Default Communication Mode. Rapid flashing LED indicates an I/O watchdog timeout has
occurred. A constant ON LED indicates an input is outside of the transmitter's
calibrated input range or an input lead is broken (when module is outside of
default mode only).
IMPORTANT: Any inputs not terminated or left open will cause the module
Status LED to turn ON and signal a lead break (out-of-range) condition. This
will mask other (flashing) conditions like default mode and watchdog timeout
indication. As such, it is recommended that unused inputs be properly terminated to avoid this condition.
Output (Yellow) - Two or four LED's, one per output. OFF if the output switch
is OFF (open), and ON if the output switch is ON (closed).
Software Configuration
The following transmitter attributes and controls are set via the DI-900MB Configuration Software (Model
100969), or any other software that supports the ModBus command/response protocol. You can use the Preset Single/Multiple Register functions to write configuration data to the appropriate register(s) as required by your application (see Register Map).
Slave Communication
Slave - ID: The Report Slave ID command will return the model number, run on/off status,
module serial number, and firmware number.
Slave - Reset: This command will trigger a reset of the module and its effect is equivalent to a
power-on reset. An alternate method of resetting a module can be accomplished via a write to the Calibration Access & Reset Register (see Memory
Map register 40024). The second approach is provided to accomplish reset
with Modbus software that does not support the Reset Slave command.
Slave - Address: Select valid slave addresses in the range of 1-247 (01H-F7H). Address 247 is
the default mode slave address.
Slave - Baud Rate: Select 2400, 4800, 9600 (default), 14400, 19200, 28800, 38400, 57600, 76800,
or 115200 bits per second.
Slave - Parity: Select Even, Odd, or No Parity (See Parity Checking) error checking. Odd or
even parity bit is followed by 1 stop bit. If no parity is selected, 2 stop bits are
used. Note that the absence of parity is equivalent to 1 stop bit and some references still refer to this as No Parity with 1 Stop Bit instead of No Parity with 2
Stop Bits.
Slave - Response Delay: Sets the minimum delay a module will wait before it sends a response to a message from the host (set 0-65500 ticks, 1.085us/tick). As a minimum, it must be
set greater than the inherent delay already present to be effective. Some signal
converters or host/software systems cannot accept a response to a message
immediately after sending the message without adding delay.
Specifications
11
Model 932MB/934MB Modbus/RS485 Network I/O Modules
Slave - Status: The Module Status Register can be used to determine alarm status, I/O watchdog timeout, A/D status, and the internal flash memory checksum error status.
Slave - Watchdog: A watchdog timer may be applied to the I/O channels of this module. Use the
Watchdog Time Register to select a timeout period from 1 to 65534 seconds
(18.2 hours). A time of 65535 (FFFFH) or 0 (0000H) will disable the I/O
watchdog timer. Use the Timeout State Register to define the states that the
outputs are to be programmed to upon I/O timeout. The four lower order bits
of this register value define the timeout states of each of the four output channels. Watchdog timeout state control takes precedence over alarm and direct
control of the output channels. Writing 65535 (FFFFH) to the Timeout States
Register will leave the port outputs unchanged upon timeout. A watchdog fault
indication flag (bit 0 of the Module Status register) will be set if any of the
module output channels have not been written to over the specified time period,
or if any of the I/O channels have not been read over the specified time period.
In addition, the module status LED will blink rapidly if a watchdog timeout
occurs. Note that alarm outputs will not change states if a timeout has occurred
until the timeout is cleared.
Analog Input
Input - Type/Range: Select one of four RTD types or resistance input. Refer to Input Specifications
for signal ranges. Note that this model uses °C or percent-of-span units.
IMPORTANT: Multiple inputs of module must be configured for the same
range/type (same gain).
Input- RTD Wiring: Select a 2-wire or 3-wire configuration.
Input- Break Detect: Select Upscale or Downscale break detection for all inputs.
Input Calibration: The configuration software can be used to calibrate the input conditioning circuit of this module (see 6. Module Software Configuration), or by using the
Preset Register Functions to write the appropriate data to the calibration registers (see Register Map).
Digital (SSR) Outputs
Output - State: The coil registers (0x references) may be read via the Read Coil (01) command
to determine the current state of the outputs. The current output state is also
indicated by a yellow status LED at the front of the module which lights when
the corresponding output switch is ON (closed), or if the corresponding input is
in alarm (but only if output is enabled as an alarm output). The Force Single
Coil (05) and Force Multiple Coil (15) commands may be used to directly control the output state via the coil registers. The outputs may also be set under
alarm control at the corresponding input channel, or via watchdog timeout control.
IMPORTANT: Alarm limits take precedence over direct control and must be
disabled if direct control is desired. Watchdog timeout control has highest priority (if enabled).
Channel Alarm Configuration
Channel - Alarm Output State & Use the Alarm Output State and Alarm Output Enable Register to enable the
Output Enable: corresponding discrete output as an alarm output and to select failsafe or nonfailsafe alarm output activation. A failsafe alarm output will turn OFF in alarm
(the same state as the power-down state). A non-failsafe alarm output will turn
ON in alarm. Alarm limit checking is always active for the module, but assignment of an alarm output is optional via this control.
Specifications
12
Model 932MB/934MB Modbus/RS485 Network I/O Modules
Channel - High Limit Value: Use the channel High Limit Value Register to write a high limit value. Limit
values use same units as input--°C for RTD inputs or scaled °percent-of-span
units for resistance input (±20000 represents ±100%). Limit values must be
within the full input range (see Analog Input Specifications). The corresponding digital output will transfer to the alarm state when the high limit value is
exceeded and remains at that state until the input signal has retreated below the
limit, plus any deadband.
Channel - Low Limit Value: Use the channel Low Limit Value Register to write a low limit value. Limit values use same units as input--°C for RTD inputs or scaled °percent-of-span units
for resistance input (±20000 represents ±100%). Limit values must be within
the full input range (see Analog Input Specifications). The corresponding digital output transfer to the alarm state when the low limit value is exceeded and
remains at that state until the input signal has retreated above the low limit,
plus any deadband.
Channel - Deadband Value: Use the channel Deadband Value Register to assign deadband to limit checking. Deadband values use scaled percent-of-span units (±20000 represents
±100%) and must be within the full input range (see Analog Input Specifications). Deadband determines the amount the input signal has to return into the
“normal” operating range before the output will turn OFF. Deadband is normally used to eliminate false trips or alarm “chatter” caused by fluctuations in
the input near the alarm point.
IMPORTANT: Noise and/or jitter on the input signal has the effect of reducing (narrowing) an instrument's deadband and may produce output chatter.
Another long term effect of output chatter is a reduction in the life of any
mechanical relay controlled via the output. To reduce this undesired effect,
increase the deadband setting.
Visual Alarm Output Indication: A yellow output LED is turned ON when the output is switched ON. This LED
can provide visual indication of when the matching input channel is in alarm if
the matching output is enabled as an alarm output (ON in alarm for the nonfailsafe mode). Alarm control of an output will take precedence over direct
control (when enabled), except for input signals in the deadband region.
Watchdog timeout control of an output will have the highest priority when
enabled.
Software Alarm Indication: The Module Status Register can be used to determine if any of the module's
inputs are in alarm. The Channel Status Register can be used determine when a
specific input is in alarm.
Other Modbus Configuration Software Capabilities
In addition to configuring all features of the module described above, the Modbus Configuration Software includes
additional capabilities for testing and control of this module as follows:
1.
Monitors the input signal values and output signal states. It also allows polling to be turned on or off.
2.
Allows a configuration to be uploaded or downloaded to/from the module via the RS485 interface.
3.
Provides controls to separately calibrate each input channel in case of error.
4.
Provides controls to reset a module.
5.
Reads the contents of the Module Status Register.
6.
Allows optional user documentation to be saved to a module file. Information includes tag number, comment,
configured by, location, and identification information. This information can also be printed via this software.
7.
Allows a module's complete configuration to be printed in an easy to read, one or two page format, including
user documentation.
Specifications
13
Model 932MB/934MB Modbus/RS485 Network I/O Modules
3. Getting Started
Unpacking and Inspection
Upon receipt of this product, inspect the shipping carton for evidence of mishandling during transit. If the shipping
carton is badly damaged or water stained, request that the carrier's agent be present when the carton is opened. If the
carrier's agent is absent when the carton is opened and the contents of the carton are damaged, keep the carton and
packing material for the agent's inspection. For repairs to a product damaged in shipment, refer to the Warranty and
Service Policy to obtain return instructions. It is suggested that salvageable shipping cartons and packing material be
saved for future use in the event the product must be shipped.
This module is physically protected with packing material and electrically
protected with an anti-static bag during shipment. However, it is recommended that the module be visually inspected for evidence of mishandling
prior to applying power.
This circuit utilizes static sensitive components and should only be handled
at a static-safe workstation.
Module Installation
This transmitter module is packaged in a general purpose plastic enclosure. Use an auxiliary enclosure to protect the
unit in unfavorable environments or vulnerable locations, or to maintain conformance to applicable safety standards.
Stay within the specified operating temperature range. As shipped from the factory, the unit is calibrated for all valid
input ranges and has the default configuration shown in the table below.
WARNING: Applicable IEC Safety Standards may require that this device be mounted within an approved metal
enclosure or sub-system, particularly for applications with exposure to voltages greater than or equal to 75VDC or
50VAC.
DI-932MB/DI-934MB Default Factory Configuration
Parameter
Configuration/Calibration
Module Address
247
Baud Rate
9600bps
Parity
None
Stop Bits
2 (When Parity=None)
Response Delay
0 (No Delay)
Watchdog Time
0 (Disabled)
Output Timeout States
All ON (Timer Disabled)
Input Range (All Inputs)
Pt 100Ω (α=1.385)
RTD Wiring
3-Wire
Sensor Break (All Inputs)
Upscale Indication
Temperature Units
°C
Limit Configuration (Each Input) Alarm Outputs Disabled
High Limit Value (Each Input)
100°C (High Endpoint)
Low Limit Value (Each Input)
0°C (Low Endpoint)
Deadband (Each Input)
1°C
Note: Do not confuse the Default Factory Configuration noted above with the Default Communication Mode, which
refers to the fixed baud rate, module address, parity, and stop bit settings achieved by pushing the Default Mode button until the status LED flashes ON/OFF. The Default Communication Mode will temporarily over-ride any factory
Getting Started
15
Model 932MB/934MB Modbus/RS485 Network I/O Modules
configuration of baud rate, module address, parity, and stop bits with settings of 9600bps, 247, None, and 2, respectively. It is provided as a convenient means of achieving communication with a module when these parameters are
unknown.
Your application will typically differ from the default factory configuration and will require that the transmitter be
reconfigured to suit your needs. This can be easily accomplished with the user-friendly Windows® DI-900MB Configuration Program. Configuration is normally done prior to field installation. Refer to MODULE SOFTWARE
CONFIGURATION of Section 3.0 for detailed instructions.
Default Mode Switch
A push-button default mode switch and status LED are provided at the front of the module as a convenient way of
communicating with the module when its baud rate and address settings are unknown. Push and hold this button until
the Status LED flashes ON/OFF to indicate the module is in the Default Communication Mode with a fixed module
address of 247, a baud rate of 9600bps, no parity, and 2 stop bits. It is most convenient to first configure a module in
this mode, then leave the default mode by pressing this button again until the Status LED stops flashing (constant ON
or OFF), or by resetting the module. The Default Mode is disabled following a software or power-on reset. New
communication parameters (for baud rate, address, and parity) will take effect following a reset of the module after
leaving the Default Mode.
IMPORTANT: The default mode is indicated via a flashing status LED. However, if an input is not terminated or
left open, the status LED will turn ON to indicate a signal over-range condition and/or break detect at one or more
input channels. This will mask default mode indication or watchdog timeout indication. As such, it is recommended
that you not leave unused channels open and properly terminate unused inputs to avoid this condition.
Mounting
Refer to Drawing 4501-897 for mounting and clearance dimensions.
DIN Rail Mounting: This module can be mounted on “T” type DIN rails. Use suitable fastening hardware to secure
the DIN rail to the mounting surface. Units may be mounted side-by-side on 1-inch centers for limited space applications.
“T” Rail (35mm), Type EN50022: To attach a module to this style of DIN rail, angle the top of the unit towards the
rail and locate the top groove of the adapter over the upper lip of the rail. Firmly push the unit towards the rail until it
snaps solidly into place. To remove a module, first separate the input terminal block(s) from the bottom side of the
module to create a clearance to the DIN mounting area. Next, insert a screwdriver into the lower arm of the DIN rail
connector and use it as a lever to force the connector down until the unit disengages from the rail.
Electrical Connections
Digital output, network, power, and input terminals can accommodate wire from 12-24 AWG, stranded or solid copper. Strip back wire insulation 1/4-inch on each lead before installing into the terminal block. Analog input wiring
should be shielded twisted-pair. Since common mode voltages can exist on signal wiring, adequate wire insulation
should be used and proper wiring practices followed. It is recommended that transmitter network, digital output, and
power wiring be separated from the input signal wiring for safety, as well as for low noise pickup. Note that input,
power, network, and digital output terminal blocks are a plug-in type and can be easily removed to facilitate module
removal or replacement, without removing individual wires. Be sure to remove power before unplugging the terminals to uninstall the module, or before attempting service. All connections must be made with power removed.
CAUTION: Risk of Electric Shock - More than one disconnect switch may be
required to de-energize the equipment before servicing.
1.
Power: Refer to Electrical Connections Drawing 4501-895. Variations in power supply voltage within rated
limits has negligible effect on module accuracy. For supply connections, use No. 14 AWG wires rated for at least
75°C. The power terminals are diode bridge-coupled and not polarized. Unit is powered from 10-36VDC, or
24VAC only.
Getting Started
16
Model 932MB/934MB Modbus/RS485 Network I/O Modules
2.
Inputs: Connect inputs per Electrical Connections Drawing 4501-895. Input supports 2-wire or 3-wire RTD
configurations only. Observe proper polarity when making input connections (see label for input type) and be
sure to include ground at the LRTN terminal.
Input Grounding: Do not connect earth ground to any of the RTD input leads or input terminals. The input
should be earth grounded at the logic return terminal (LRTN, TB3-6) only.
IMPORTANT: Noise and/or jitter on the input signal has the effect of reducing (narrowing) the instrument's
deadband and may produce switch chatter when using the alarm output. The long term effect of chatter will
reduce the life of any mechanical relays that may be connected to these outputs. To reduce this undesired effect,
you should increase the effective deadband.
3.
Outputs (Coils): Outputs are solid-state switches that share a common return (RTN) and are intended for DC
switching applications only. Observe proper polarity when making connections. Each output includes a transient voltage suppresser, a snubber diode, plus an integrated snubber, but may still require additional protection
when switching inductive loads (see below). Refer to the SPECIFICATIONS section for output specifications
and the module's side label for terminal designations. The output circuits as a group are electrically isolated. If
necessary, an interposing relay can be used to switch higher currents as illustrated in the Interposing Relay Connection Drawing 4501-896.
Note: The outputs go to their OFF state (open) following a software or power-on reset of the module. Outputs
may be optionally sent to a user-defined state following a watchdog timer timeout.
IMPORTANT - Protection With Inductive Loads: The outputs include reverse-bias shunt diodes connected
to help protect the solid-state switch from damage due to reverse emf voltages that are generated in switching
inductive loads. However, you should add external protection local to the inductive load to prevent this emf from
being distributed across the connection media. For DC inductive loads, place a diode across the load (1N4006 or
equivalent) with cathode to (+) and anode to (-).
4.
Network Connections: Wire network as shown in Network Connections Drawing 4501-805. Network common
(COM) should connect to earth ground at one point.
5.
Grounding: See Electrical Connections Drawing 4501-895 for application of earth ground. The module housing is plastic and does not require an earth ground connection.
WARNING: For compliance to applicable safety and performance standards, the use
of shielded cable is recommended as shown in Drawing 4501-895. Further, the application of earth ground must be in place as shown in Drawing 4501-895. Failure to
adhere to sound wiring and grounding practices may compromise safety & performance.
Software Installation
The 900MB Configuration Software is used to configure Series DI-900MB modules and is installed as follows:
1.
Insert the DI-900MB Resource CD into your CD-ROM drive.
IMPORTANT: Before continuing with installation, be sure to exit any other Windows programs that may be
running.
2.
The Window’s AutoRun feature should start the CD and the installation software will run.
3.
Select the option “Install DI-900MB Configuration Software” and click on OK.
4.
The Welcome Dialog Box appears. Click on Next to continue with the installation or Cancel to abort.
Getting Started
17
Model 932MB/934MB Modbus/RS485 Network I/O Modules
5.
Fill out your user information in the appropriate text boxes and click on Next.
6.
The Choose Destination dialog box allows you to specify the program files’ destination directory. To keep the
default (C:\Program Files\Series900MB) click on Next, to change the destination click on the Browse button,
select a destination, then click on Next.
7.
The Select Program Folder allows you to designate the program folder. To keep the default (Series900MB),
click on Next, to choose a different folder, make a selection from the list then click on Next.
8.
The Start Copying Files dialog box shows the current settings and allows you to change them by using the Back
button. To change settings, click on the Back button until you reach the setting you would like to change, change
that setting, and click on the Next button until you get back to the Start Copying Files dialog box. To keep the
current settings and install the software, click on the Next button.
9.
Setup is complete. Click Finish to exit the DATAQ installation program and return to Windows.
10. To run the configuration software, go to the Start Menu and click on Programs > Series900MB > Series900MB
Configuration (this is the default - if you did not keep the default settings choose the program folder and directory you had specified during installation).
Getting Started
18
Model 932MB/934MB Modbus/RS485 Network I/O Modules
4. Module Configuration
This module needs to be configured for your application. Configuration is easily accomplished using the Windows®
Series DI-900MB Configuration Software and an RS232-to-RS485 signal converter. It is not required to use the Configuration software to communicate with the Series DI-900MB, as any software capable of sending Modbus protocol
commands over an RS485 interface can be used. However, the Configuration software provides an easy to use Windows format for communicating with the module that does not require advanced familiarity with the Modbus protocol.
Register Map
Modbus registers are organized into the following reference types identified by the leading number of the reference
address:
Reference
0xxxx
1xxxx
3xxxx
4xxxx
Description
Read/Write Discrete Outputs or Coils. A 0x reference address is used to drive output data
to a digital output channel.
Read Discrete Inputs. The ON/OFF status of a 1x reference is controlled by the corresponding digital input channel.
Read Input Registers. A 3x reference register contains a 16-bit number received from an
external source-e.g. an analog signal.
Read/Write Output or Holding Registers. A 4x register is used to store 16-bits of numerical data (binary or decimal), or to send the data from the CPU to an output channel.
Notes:
1.
The “x” following the leading character represents a four-digit address location in user data memory. The leading character is generally implied by the function code and omitted from the address specifier for a given function. The leading character also identifies the I/O data type.
2.
The ON/OFF state of discrete inputs and outputs is represented by a 1 or 0 value assigned to an individual bit in
a 16-bit data word. With respect to mapping, the LSB of the word maps to the lowest numbered channel of a
group and channel numbers increase sequentially as you move towards the MSB. Unused bits are set to zero.
Modbus functions operate on register map registers to configure and control module I/O. The following table outlines the register map for both Model DI-932MB and DI-934MB network I/O modules. Some registers are applicable
to DI-934MB models only, which include two additional input channels. You will find it helpful to refer to this map
as you review the Modbus function descriptions given later.
Module Configuration
19
Model 932MB/934MB Modbus/RS485 Network I/O Modules
Ref
Addr.
Description
Coil Registers (0x References, Read/Write)
00001 0-3 (0000Up to Four Discrete
Thru
0003)
Outputs 0-3
00004
Note: After reset, these registers read 0 (outputs OFF) and
these registers are not maintained in EEPROM.
Input Registers (3x References, Read-Only)
30001
0 (0000)
Module Status
30002
1 (0001)
Current Global Input Configuration
Register
DI-932MB and DI-934MB
Models
Note: Applies to all inputs
together.
30003
2 (0002)
CH 0 Input Value
Data Type/Format
Discrete Output Value. Addresses a specific bit of a 16bit word that controls/ monitors the ON/OFF status for
the output.
A set bit (1) means the corresponding output is ON
(closed). A clear bit (0) means the corresponding output is OFF (open). The bit position corresponds to the
output channel number (i.e. output 0 uses bit 0 of the
16-bit word at address 0, output 1 uses bit 1 of the 16bit word at address 1, etc.) Unused bits of a word are
set to 0.
Bits 15-4: Not Used. Additionally, unused bits in
range 3-0 are set to 0.
IMPORTANT: Disable the corresponding limits if
you wish to control the state of a discrete output
directly via these registers, as limit alarm control will
take precedence.
Bit 15: Flash Checksum; 1 = Error Flag; 0 = No Flash
Error
Bit 14: A/D Error Flag; 1 = A/D Error; 0 = No A/D
Error
Bit 13: Default Mode Flag; 1 = Default Mode Indication; 0 = Not In Default Mode
Bits 12-4: Zero
Bit 3: I/O Watchdog Fault; 1 = Watchdog Timeout; 0 =
No Timeout
Bit 2: Global Limit Exc.; 1 = Global Limit Exceeded; 0
= No Limit Exceeded
Bit 1: Break Detect Flag; 1 = Upscale Break; 0 =
Downscale Break
Bit 0: Zero
Bit 15: Input Wiring; 0 = 2-Wire Mode; 1 = 3-Wire
Mode
Bits 14-4: Reserved
Bits 3,2,1,0: Input Range
0000 = 0 =Pt 100Ω, 3-Wire (α=1.3850, -200 to 850°C)
0001 = 1 =Pt 100Ω, 3-Wire (α=1.3911, -200 to 850°C)
0010 = 2 =Ni 120Ω, 3-Wire (α=1.6720, - 80 to 320°C)
0011 = 3 =Cu 10Ω, 3-wire (α=1.4272, -200 to 260°C)
0100 = 4 =Res, 3-wire(Linear 0 to 500Ω, 3-Wire)
0101 = 5 =Pt 100Ω, 2-Wire (α=1.3850, -200 to 850°C)
0110 = 6 =Pt 100Ω, 2-Wire (α=1.3911, -200 to 850°C)
0111 = 7 =Ni 120Ω, 2-Wire (α=1.6720, - 80 to 320°C)
1000 = 8 =Cu 10Ω, 2-wire (α=1.4272, -200 to 260°C)
1001 = 9 =Res, 2-wire(Linear 0 to 500Ω, 2-Wire)
1xxx = 10-15 = Reserved
Temperature (°C) or Percentage (%)
Module Configuration
20
Model 932MB/934MB Modbus/RS485 Network I/O Modules
Ref
30004
Addr.
3 (0003)
Description
CH 0 Status Value
Data Type/Format
Bits 15-4: Zero
Bit 3: High Limit Flag; 1 = High Limit Exceeded; 0 =
Below High Limit
Bit 2: Low Limit Flag; 1 = Low Limit Exceeded; 0 =
Above Low Limit
Bits 1,0: Under/Over Range
00 = In Range; 01 = Overrange; 10 = Under Range; 11
= Not Defined
Temperature (°C) or Percentage (%)
Format Is Same As CH 0
Temperature (°C) or Percentage (%)
Format Is Same As CH 0
Temperature (°C) orPercentage (%)
Format Is Same As CH 0
30005
30006
30007
30008
30009
30010
30011
4 (0004)
5 (0005)
6 (0006)
7 (0007)
8 (0008)
9 (0009)
10 (000A)
CH 1 Input Value
CH 1 Status Value
CH 2 Input Value
CH 2 Status Value
CH 3 Input Value
CH 3 Status Value
CH 0 Raw Count
30012
11 (000B)
CH 1 Raw Count
Raw A/D Count Value3
30013
12 (000C)
CH 2 Raw Count
Raw A/D Count Value3
30014
13 (000D)
CH 3 Raw Count
Raw A/D Count Value3
Raw A/D Count Value3
Holding Registers (4x References, Read/Write)
Note: Changes to Holding Registers take effect following the next software or power-on reset of the module,
except where noted otherwise.
40001
0 (0000)
Slave AddressDefault=247
1 through 247 (Default)
40002
1 (0001)
Baud Rate Default=2, 9600bps 0 = 2400bps
1 = 4800bps
2 = 9600bps (Default)
3 = 14400bps
4 = 19200bps
5 = 28800bps
6 = 38400bps
7 = 57600bps
8 = 76800bps
9 = 115200bps
40003
2 (0002)
Parity Default=0, None
0 = None (2 stop bits)
1 = Odd Parity Checking (1 stop bit)
2 = Even Parity Checking (1 stop bit)
40004
3 (0003)
I/O Watchdog Time Default=0, Can be set from 1 to 65534 seconds. Set to 65535
Disabled
(FFFFH) or 0 (0000H) to disable the watchdog timer
(0000H/disabled is the default value).
40005
4 (0004)
Output Channel Timeout
The four lower order bits of this 16-bit register value
States Default=65535, Disdefine the state the output channels will be programmed
to following a watchdog timeout. Bit 0 corresponds to
abled
channel 0, bit 1 to channel 1, bit 2 to channel 2, and bit
3 to channel 4. Write 65535 (FFFFH) to this register to
leave the outputs unchanged following a timeout (this is
also the default value). Note that watchdog timeout
control takes precedence over alarm and direct control
of the output relay.
Module Configuration
21
Model 932MB/934MB Modbus/RS485 Network I/O Modules
Ref
40006
Addr.
5 (0005)
Description
Response Delay Time (Turnaround Delay) Default=0, No
Delay
Data Type/Format
Can be set from 0 to 65535 ticks (1 tick = 1.085us).
This is the additional delay the module will wait before
responding to a host message. The default value is 0
(no delay). Increase this value if you are having communication problems or you encounter a high degree of
error messages.
Bit 15-2: 0 (Not Used)
Bit 1: RTD Break Status; 1 = Upscale Break; 0 =
Downscale Break6
Bit 0: 0 (Not Used)
Bit 15: Input Wiring; 0 = 2-Wire Mode; 1 = 3-Wire
Mode
Bits 14-4: Reserved
Bits 3,2,1,0: Input Range
0000 = 0 =Pt 100Ω, 3-Wire (α=1.3850, -200 to 850°C)
0001 = 1 =Pt 100Ω, 3-Wire (α=1.3911, -200 to 850°C)
0010 = 2 =Ni 120Ω, 3-Wire (α=1.6720, - 80 to 320°C)
0011 = 3 =Cu 10Ω, 3-wire (α=1.4272, -200 to 260°C)
0100 = 4 =Res,6 3-Wire,(Linear 0 to 500Ω, 3-Wire)
0101 = 5 =Pt 100Ω, 2-Wire (α=1.3850, -200 to 850°C)
0110 = 6 =Pt 100Ω, 2-Wire (α=1.3911, -200 to 850°C)
0111 = 7 =Ni 120Ω, 2-Wire (α=1.6720, - 80 to 320°C)
1000 = 8 =Cu 10Ω, 2-wire (α=1.4272, -200 to 260°C)
1001 = 9 =Res,6 2-Wire(Linear 0 to 500Ω, 2-Wire)
1xxx = 10-15 = Reserved
40007
6 (0006)
Break Detect (applies to all
inputs)6 Default=0, Upscale
40008
7 (0007)
DI-932/DI-934MB Global
Input Configuration (applies to
all inputs) Default=0, Pt 100Ω
(α=1.385)
40009
8 (0008)
Temperature (°C) or Percentage (%)5
40010
9 (0009)
40011
10 (000A)
40012
11 (000B)
CH0 High Limit
Default=850°(Pt), 320°(Ni),
260°(Cu), or 100%(Res.)
CH0 Low Limit Default=200°(Pt/Cu), -80° (Ni), or
0%(Resistance)
CH0 Deadband Default=1°C,
1% (Res.)
CH0 Alarm Output State &
Alarm Output Enable
Default=0, Disabled
40013
12 (000C)
Temperature (°C) or Percentage (%)5
40014
13 (000D)
40015
14 (000E)
CH1 High Limit
Default=850°(Pt), 320°(Ni),
260°(Cu), or 100%(Res.)
CH1 Low Limit Default=200°(Pt/Cu), -80° (Ni), or 0%
(Resistance)
CH1 Deadband Default=1°C,
1% (Res.)
Temperature (°C) or Percentage (%)5
Temperature (°C) or Percentage (%)5
Bits 15-3: Zero
Bit 2: Alarm Out State; 0 = Failsafe (OFF); 1 = NonFailsafe (ON)
Bit 1: High Limit; 1 = Hi Output Enabled; 0 = Hi Output Disabled
Bit 0: Low Limit; 1 = Lo Output Enabled; 0 = Lo Output Disabled
Temperature (°C) or Percentage (%)5
Temperature (°C) or Percentage (%)5
Module Configuration
22
Model 932MB/934MB Modbus/RS485 Network I/O Modules
Ref
40016
Addr.
15 (000F)
40017
16 (0010)
40018
17 (0011)
40019
18 (0012)
40020
19 (0013)
40021
20 (0014)
40022
21 (0015)
40023
22 (0016)
40024
23 (0017)
40027
40028
Description
CH1 Alarm Output State &
Alarm Output Enable
Default=0, Disabled
Data Type/Format
Bits 15-3: Zero
Bit 2: Alarm Out State; 0 = Failsafe (OFF); 1 = NonFailsafe (ON)
Bit 1: High Limit; 1 = Hi Output Enabled; 0 = Hi Output Disabled
Bit 0: Low Limit; 1 = Lo Output Enabled; 0 = Lo Output Disabled
CH2 High Limit
Default=850°(Pt), 320°(Ni),
260°(Cu), or 100%(Res.)
CH2 Low Limit Default=200°(Pt/Cu), -80° (Ni), or
0%(Res.)
CH2 Deadband Default=1°C,
1% (Res.)
CH2 Alarm Output State &
Alarm Output Enable
Default=0, Disabled
Temperature (°C) or Percentage (%)5
CH3 High Limit
Default=850°(Pt), 320°(Ni),
260°(Cu), or 100%(Res.)
CH3 Low Limit Default=200°(Pt/Cu), -80° (Ni), or
0%(Res.)
CH3 Deadband Default=1°C,
1%(Res.)
CH3 Alarm Output State &
Alarm Output Enable
Default=0, Disabled
Temperature (°C) or Percentage (%)5
26 (001A)
CH0 Pt385 3W Cal Low Value
Raw A/D Count Value3
27 (001B)
CH0 Pt391 3W Cal High Value
Raw A/D Count Value3
Temperature (°C) or Percentage (%)5
Temperature (°C) or Percentage (%)5
Bits 15-3: Zero
Bit 2: Alarm Out State; 0 = Failsafe (OFF); 1 = NonFailsafe (ON)
Bit 1: High Limit; 1 = Hi Output Enabled; 0 = Hi Output Disabled
Bit 0: Low Limit; 1 = Lo Output Enabled; 0 = Lo Output Disabled
Temperature (°C) or Percentage (%)5
Temperature (°C) or Percentage (%)5
Bits 15-3: Zero
Bit 2: Alarm Out State; 0 = Failsafe (OFF); 1 = NonFailsafe (ON)
Bit 1: High Limit; 1 = Hi Output Enabled; 0 = Hi Output Disabled
Bit 0: Low Limit; 1 = Lo Output Enabled; 0 = Lo Output Disabled
40025
24 (0018)
Calibration Access
Writing 24106 (5E2AH) here immediately removes
write protection from the calibration registers that folAnd
low. All other values apply write protection to the caliAlternate Method of Module
bration registers (except 41429).
Reset
Writing 41429 (A1D5H) to this register will cause an
immediate module reset. This is provided as an alternate method of Reset for software that does not support
the Reset Slave (08) command.
After a reset, this register reads 0 (write protection
enabled and no reset).
This register is not maintained in EEPROM.
IMPORTANT: Access to calibration registers 40026 through 40115 is not normally required and writes to these
registers should be avoided to prevent module miscalibration. Registers 40066-40105 are applicable to Model DI934MB only, which has two additional channels.
40026
25 (0019)
CH0 Pt385 3W Cal High Value Raw A/D Count Value3
Module Configuration
23
Model 932MB/934MB Modbus/RS485 Network I/O Modules
Ref
40029
Addr.
28 (001C)
Description
CH0 Pt391 3W Cal Low Value
Data Type/Format
Raw A/D Count Value3
40030
29 (001D)
CH0 Ni 3W Cal High Value
Raw A/D Count Value3
40031
30 (001E)
CH0 Ni 3W Cal Low Value
Raw A/D Count Value3
40032
31 (001F)
CH0 Cu 3W Cal High Value
Raw A/D Count Value3
40033
32 (0020)
CH0 Cu 3W Cal Low Value
Raw A/D Count Value3
40034
33 (0021)
Raw A/D Count Value3
40035
34 (0022)
40036
35 (0023)
CH0 0-500Ω 3W Resistance
Cal HI Value
CH0 0-500Ω 3W Resistance
Cal LO Value
CH0 Pt385 2W Cal High Value
40037
36 (0024)
CH0 Pt385 2W Cal Low Value
Raw A/D Count Value3
40038
37 (0025)
CH0 Pt391 2W Cal High Value
Raw A/D Count Value3
40039
38 (0026)
CH0 Pt391 2W Cal Low Value
Raw A/D Count Value3
40040
39 (0027)
CH0 Ni 2W Cal High Value
Raw A/D Count Value3
40041
40 (0028)
CH0 Ni 2W Cal Low Value
Raw A/D Count Value3
40042
41 (0029)
CH0 Cu 2W Cal High Value
Raw A/D Count Value3
40043
42 (002A)
CH0 Cu 2W Cal Low Value
Raw A/D Count Value3
40044
43 (002B)
Raw A/D Count Value3
40045
44 (002C)
40046
45 (002D)
CH0 0-500Ω 2W Resistance
Cal HI Value
CH0 0-500Ω 2W Resistance
Cal LO Value
CH1 Pt385 3W Cal High Value
40047
46 (002E)
CH1 Pt385 3W Cal Low Value
Raw A/D Count Value3
40048
47 (002F)
CH1 Pt391 3W Cal High Value
Raw A/D Count Value3
40049
48 (0030)
CH1 Pt391 3W Cal Low Value
Raw A/D Count Value3
40050
49 (0031)
CH1 Ni 3W Cal High Value
Raw A/D Count Value3
40051
50 (0032)
CH1 Ni 3W Cal Low Value
Raw A/D Count Value3
40052
51 (0033)
CH1 Cu 3W Cal High Value
Raw A/D Count Value3
40053
52 (0034)
CH1 Cu 3W Cal Low Value
Raw A/D Count Value3
40054
53 (0035)
Raw A/D Count Value3
40055
54 (0036)
40056
55 (0037)
CH1 0-500Ω Resistance 3W
Cal HI Value
CH1 0-500Ω Resistance 3W
Cal LO Value
CH1 Pt385 2W Cal High Value
40057
56 (0038)
CH1 Pt385 2W Cal Low Value
Raw A/D Count Value3
40058
57 (0039)
CH1 Pt391 2W Cal High Value
Raw A/D Count Value3
40059
58 (003A)
CH1 Pt391 2W Cal Low Value
Raw A/D Count Value3
40060
59 (003B)
CH1 Ni 2W Cal High Value
Raw A/D Count Value3
40061
60 (003C)
CH1 Ni 2W Cal Low Value
Raw A/D Count Value3
40062
61 (003D)
CH1 Cu 2W Cal High Value
Raw A/D Count Value3
40063
62 (003E)
CH1 Cu 2W Cal Low Value
Raw A/D Count Value3
Raw A/D Count Value3
Raw A/D Count Value3
Raw A/D Count Value3
Raw A/D Count Value3
Raw A/D Count Value3
Raw A/D Count Value3
Module Configuration
24
Model 932MB/934MB Modbus/RS485 Network I/O Modules
Ref
40064
Addr.
63 (003F)
40065
64 (0040)
40066
65 (0041)
Description
CH1 0-500Ω Resistance 2W
Cal HI Value
CH1 0-500Ω Resistance 2W
Cal LO Value
CH2 Pt385 3W Cal High Value
Data Type/Format
40067
66 (0042)
CH2 Pt385 3W Cal Low Value
Raw A/D Count Value3
40068
67 (0043)
CH2 Pt391 3W Cal High Value
Raw A/D Count Value3
40069
68 (0044)
CH2 Pt391 3W Cal Low Value
Raw A/D Count Value3
40070
69 (0045)
CH2 Ni 3W Cal High Value
Raw A/D Count Value3
40071
70 (0046)
CH2 Ni 3W Cal Low Value
Raw A/D Count Value3
40072
71 (0047)
CH2 Cu 3W Cal High Value
Raw A/D Count Value3
40073
72 (0048)
CH2 Cu 3W Cal Low Value
Raw A/D Count Value3
40074
73 (0049)
Raw A/D Count Value3
40075
74 (004A)
40076
75 (004B)
CH2 0-500Ω 3W Resistance
Cal HI Value
CH2 0-500Ω 3WResistance
Cal LO Value
CH2 Pt385 2W Cal High Value
40077
76 (004C)
CH2 Pt385 2W Cal Low Value
Raw A/D Count Value3
40078
77 (004D)
CH2 Pt391 2W Cal High Value
Raw A/D Count Value3
40079
78 (004E)
CH2 Pt391 2W Cal Low Value
Raw A/D Count Value3
40080
79 (004F)
CH2 Ni Cal 2W High Value
Raw A/D Count Value3
40081
80 (0050)
CH2 Ni Cal 2W Low Value
Raw A/D Count Value3
40082
81 (0051)
CH2 Cu Cal 2W High Value
Raw A/D Count Value3
40083
82 (0052)
CH2 Cu Cal 2W Low Value
Raw A/D Count Value3
40084
83 (0053)
Raw A/D Count Value3
40085
84 (0054)
40086
85 (0055)
CH2 0-500Ω Resistance 2W
Cal HI Value
CH2 0-500Ω Resistance 2W
Cal LO Value
CH3 Pt385 3W Cal High Value
40087
86 (0056)
CH3 Pt385 3W Cal Low Value
Raw A/D Count Value3
40088
87 (0057)
CH3 Pt391 3W Cal High Value
Raw A/D Count Value3
40089
88 (0058)
CH3 Pt391 3W Cal Low Value
Raw A/D Count Value3
40090
89 (0059)
CH3 Ni Cal 3W High Value
Raw A/D Count Value3
40091
90 (005A)
CH3 Ni Cal 3W Low Value
Raw A/D Count Value3
40092
91 (005B)
CH3 Cu Cal 3W High Value
Raw A/D Count Value3
40093
92 (005C)
CH3 Cu Cal 3W Low Value
Raw A/D Count Value3
40094
93 (005D)
Raw A/D Count Value3
40095
94 (005E)
40096
95 (005F)
CH3 0-500Ω 3W Resistance
Cal HI Value
CH3 0-500Ω 3W Resistance
Cal LO Value
CH3 Pt385 2W Cal High Value
40097
96 (0060)
CH3 Pt385 2W Cal Low Value
Raw A/D Count Value3
Raw A/D Count Value3
Raw A/D Count Value3
Raw A/D Count Value3
Raw A/D Count Value3
Raw A/D Count Value3
Raw A/D Count Value3
Raw A/D Count Value3
Raw A/D Count Value3
Raw A/D Count Value3
Module Configuration
25
Model 932MB/934MB Modbus/RS485 Network I/O Modules
Ref
40098
Addr.
97 (0061)
Description
CH3 Pt391 2W Cal High Value
Data Type/Format
Raw A/D Count Value3
40099
98 (0062)
CH3 Pt391 2W Cal Low Value
Raw A/D Count Value3
40100
99 (0063)
CH3 Ni 2W Cal High Value
Raw A/D Count Value3
40101
100 (0064)
CH3 Ni 2W Cal Low Value
Raw A/D Count Value3
40102
101 (0065)
CH3 Cu 2W Cal High Value
Raw A/D Count Value3
40103
102 (0066)
CH3 Cu 2W Cal Low Value
Raw A/D Count Value3
40104
103 (0067)
Raw A/D Count Value3
40105
104 (0068)
40106
105 (0069)
CH3 0-500Ω 2W Resistance
Cal HI Value
CH3 0-500Ω 2WResistance
Cal LO Value
Pt385 Input Range High
40107
106 (006A)
Pt385 Input Range Low
Ideal A/D Count Value3
40108
107 (006B)
Pt391 Input Range High
Ideal A/D Count Value3
40109
108 (006C)
Pt391 Input Range Low
Ideal A/D Count Value3
40110
109 (006D)
Ni Input Range High
Ideal A/D Count Value3
40111
110 (006E)
Ni Input Range Low
Ideal A/D Count Value3
40112
111 (006F)
Cu Input Range High
Ideal A/D Count Value3
40113
112 (0070)
Cu Input Range Low
Ideal A/D Count Value3
40114
113 (0071)
0-500Ω Input Range High
Ideal A/D Count Value3
40115
114 (0072)
0-500Ω InputRange Low
Ideal A/D Count Value3
Raw A/D Count Value3
Ideal A/D Count Value3
Notes (Register Map):
1.
2.
3.
4.
5.
6.
Note that the Report Slave ID and Reset Slave functions do not operate on Register Map locations. An alternate
method of accomplishing reset is provided if your software does not support the Reset Slave function (see Register 40025).
Configuration variables stored in holding registers (4xxxx reference addresses) are maintained in EEPROM.
Changes to these registers do not take effect until the next software or power-on reset of the module, except for
the Calibration Access & Reset Register which takes effect immediately.
TheDI-932MB/DI-934MB A/D Count value is calculated via the expression: count = (32768*Vin*Gain/
Vref)+32768, where Vref=1.020V (1020Ω*0.001mA). Gain is 2 (Pt), 2 (Ni), 8 (Cu), and 2 (0-500Ω).
WARNING: Access to shaded calibration registers 40026 through 40115 is not normally required and writes to
these registers should be avoided to prevent miscalibration.
RTD input values are represented via 16-bit signed integer values with a resolution of 0.1°C/lsb and a possible
range of -3276.8°C to +3276.7°C. Default limit values are set to the RTD input range endpoints: -200°C (Pt/Cu)
or -80°C (Ni) for the Low Limit, and +850°C (Pt), +320°C (Ni), or +260°C (Cu) for the High Limit. Default
deadband is set to 1.0°C. The 0-500Ω input range values are represented via 16-bit signed integers representing
percent with a resolution of 0.005%/lsb. The full range is -163.84% (-32768 decimal) to +163.835% (+32767
decimal). That is, ±20000 is used to represent ±100% (a span of -20000 to +20000). For example, 0% and 100%
are represented by decimal values 0 and 20000, respectively. Default limit values are set to the input range endpoints: 0% (Low Limit, 0 count at 0Ω) and +100% (High Limit, +20000 count at 500Ω). Default deadband is set
to 1% of span (a count of 200). Limit checking is always active.
IMPORTANT - Break detection with 0-500 ohm inputs: The maximum input resistance including lead wires is
approximately 506Ω. If break detection is set to downscale and your input resistance is greater than 505Ω (saturated), this will trigger break detection and the input reading will be sent downscale for the over-range input
resistance without actual lead breakage. Likewise, upscale break detect is not distinguishable from an input
resistance greater than 505Ω.
Module Configuration
26
Model 932MB/934MB Modbus/RS485 Network I/O Modules
5. An Introduction to Modbus
The Modbus protocol provides an industry standard method that Series DI-900MB modules use for parsing messages. Modbus devices communicate using a master-slave technique in which only one device (the master) can initiate transactions (called queries). The other devices (slaves) respond by supplying the requested data to the master,
or by taking the action requested in the query. DI-900MB modules are slaves, while a typical master device is a host
computer running appropriate application software. Masters can address individual slaves, or can initiate a broadcast
message to all slaves. Slaves return a response to all queries that are addressed to them individually, but no response
is returned to broadcast queries from a master device.
Remote Terminal Unit (RTU) Mode
Series DI-900MB modules use the widely accepted Modbus network protocol in the RTU (Remote Terminal Unit)
serial transmission mode. In RTU mode, each 8-bit message byte contains two 4-bit hexadecimal characters, and the
message is transmitted in a continuous stream. The format for each byte in RTU mode is outlined below:
RTU Mode Byte Format
Coding System
8-bit binary, hexadecimal 0-9, A-F, two hexadecimal characters contained in
each 8-bit field of the message.
Bits Per Byte
1 start bit + 8 data bits, lsb sent first + 1bit for even/odd parity or no bit for no
parity + 1 stop bit if parity is used or 2 stop bits with no parity.
Error Check Field
Cyclical Redundancy Check (CRC)
A master’s query is comprised of a slave address (or broadcast address), a function code defining the requested
action, any required data, and an error checking field. A slave's response is comprised of fields confirming the action
taken, any data to be returned, and an error checking field. The query and response both include a device address +
function code + data byte(s) + error checking field. If an error occurred in the receipt of the query, or if the slave is
unable to perform the requested action, the slave will return an exception message as its response (see Modbus
Exceptions). The error check field allows the master to confirm that the message contents are valid.
Modbus Message Framing
A Modbus message is placed in a frame by the transmitting device. A frame is used to mark the beginning and ending point of a message allowing the receiving device to determine which device is being addressed and to know when
the message is completed. It also allows partial messages to be detected and errors flagged as a result.
RTU mode messages start with a silent interval of at least 3.5 character times implemented as a multiple of character
times at the baud rate being used on the network (indicated as t1t2t3t4 below). The first field transmitted is the device
address. The allowable characters transmitted for all fields are hexadecimal values 0-9, A-F. A networked device
continuously monitors the network, including the silent intervals, and when the first field is received (the address),
the device decodes it to determine if it is the addressed device. Following the last character transmitted, a similar
silent interval of 3.5 character times marks the end of the message and a new message can begin after this interval. A
typical message frame is shown below.
RTU Message Frame
Start
Addr.
t1t2t3t4
8 bits
Function
8 bits
Data
nx8 bits
CRC
16 bits
End
t1t2t3t4
The entire message must be transmitted as a continuous stream. If a silent interval of more than 1.5 character times
occurs before completion of the frame, the receiving device flushes the incomplete message and assumes the next
byte will be the address field of a new message.
An Introduction to Modbus
27
Model 932MB/934MB Modbus/RS485 Network I/O Modules
In similar fashion, if a new message begins earlier than 3.5 character times following a previous message, the receiving device assumes it is a continuation of the previous message. This will generate an error, as the value in the final
CRC field will not be valid for the combined messages.
How Characters Are Transmitted Serially
When messages are transmitted on Modbus serial networks, each character or byte is sent in the order of Least Significant Bit (LSB) to Most Significant Bit (MSB) as outlined below (moving left to right). Note that an additional stop
bit is transmitted to fill out the character frame for no parity.
RTU Character Framing (No Parity)
Start
0
1
2
3
4
5
6
7
Stop
Stop
RTU Character Framing (With Parity)
Start
0
1
2
3
4
5
6
7
Parity
Stop
Modbus Addresses
The master device addresses a specific slave device by placing the 8-bit slave address in the address field of the message. Valid addresses are from 1-247. When the slave responds, it places its own address in this field of its response
to let the master know which slave is responding. Address 0 is reserved for the broadcast address, which all slave
devices on a network recognize. A slave does not issue a response to broadcast messages. Further, not all function
messages support the broadcast address.
With respect to data addresses, all data addresses in Modbus messages are referenced to 0, with the first occurrence of
a data item addressed as item number zero. Further, a function code field already specifies which register group it is
to operate on (i.e. 0x, 1x, 3x, or 4x reference addresses). For example, holding register 40001 is addressed as register
0000 in the data address field of the message. The function code that operates on this register specifies a “holding
register” operation and the “4xxxx” reference is implied. Holding register 40108 is addressed as register 006BH (107
decimal).
Modbus Functions
The function code field of a message frame contains the 8 bits that tell the slave what kind of action to take. Valid
codes are in the range 1-255. Not all codes apply to a module and some codes are reserved for future use. The following table highlights the subset of standard Modbus functions supported by the Model DI-932MB/DI-934MB
module (the reference register addresses that the function operates on are also indicated):
Code
01 (01H)
03 (03H)
04 (04H)
05 (05H)
06 (06H)
08 (08H)
15 (0FH)
16 (10H)
17 (11H)
Function
Read Coil (Output) Status
Read Holding Registers
Read Input Registers
Force Single Coil (Output)
Preset Single Register
Reset Slave
Force Multiple Coils (Outputs)
Preset Multiple Registers
Report Slave ID
Reference
0xxxx
4xxxx
3xxxx
0xxxx
4xxxx
Hidden
0xxxx
4xxxx
Hidden
These functions are used to access the registers outlined in the register map presented in the prior section for sending
and receiving data. Note that the Report Slave ID and Reset Slave commands do not operate on register map registers.
When the slave device responds to the master, it uses the function code field to indicate either a normal (error-free)
response, or that some kind of error has occurred (an exception response). A normal response simply echoes the original function code of the query, while an exception response returns a code that is equivalent to the original function
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Model 932MB/934MB Modbus/RS485 Network I/O Modules
code with its most significant bit (msb) set to a logic 1. For example, the Read Holding Registers command has the
function code 0000 0011 (03H). If the slave device takes the requested action without error, it returns the same code
in its response. However, if an exception occurs, it returns 1000 0011 (83H) in the function code field and also
appends a unique code in the data field of the response message that tells the master device what kind of error
occurred, or the reason for the exception (See Modbus Exceptions). The master's application program must handle
the exception response. It may choose to post subsequent retries of the original message, it may try sending diagnostic messages to the slave, or it may simply notify the operator an exception error has occurred.
The following paragraphs describe the Modbus functions supported by this model. To gain a better understanding of
Modbus, please refer to the Register Map as you review this material.
Read Coil Status (01)
This command will read the ON/OFF status of discrete outputs or coils (0x reference addresses) in the slave. For DI932MB/DI-934MB models, its response is equivalent to reading the on/off status of the solid-state output relays.
Broadcast transmission is not supported.
The Read Coil Status query specifies the starting coil (output channel) and quantity of coils to be read. Coils correspond to the discrete solid-state relays of this transmitter and are addressed starting from 0 (up to 4 coils addressed as
0-3 for this model).
The Read Coil Status in the response message is packed as one coil or channel per bit of the data field. The output
status is indicated as 1 for ON (conducting current), and 0 for OFF (not conducting). The LSB of the first data byte
corresponds to the status of the coil addressed in the query. The other coils follow sequentially, moving toward the
high order end of the byte. Since this model has only 4 outputs, the remaining bits of the data byte will be set to zero
toward the unused high order end of the byte.
The following example reads the output channel status of coils 0-3 at slave device 247:
Read Coil Status Example Query
Field Name
Slave Address
Function Code
Starting Address High Order
Starting Address Low Order
Number Of Points High Order
Number Of Points Low Order
Error Check (LRC or CRC)
Read Coil Status Example Response
Field Name
Example Value
(Hex)
Slave Address
247 (F7)
Function Code
1 (01)
Byte Count
1 (01)
Data (Coils 3-0)
10 (0A)
Error Check (LRC or CRC)
--
Example
Value (Hex)
247 (F7)
1 (01)
0 (00)
0 (00)
0 (00)
4 (04)
--
Note that the leading character of the 0x reference address is implied by the function code and omitted from the
address specified. In this example, the first address is 00001, referenced via 0000H, and corresponding to coil 0.
To summarize, the status of coils 3-0 is shown as the byte value 0A hex, or 00001010 binary. Coil 3 is the fifth bit
from the left of this byte, and coil 0 is the LSB. The four remaining bits (toward the high-order end) are zero. Reading left to right, the output status of coils 3..0 is ON-OFF-ON-OFF. This is summarized as follows:
Bin
Hex
Coil
0
0
0
0
1
0
0
NA
NA
1
0
1
0
A
NA
NA
3
2
Read Holding Registers (03)
This command will read the binary contents of holding registers (4x reference addresses) in the slave device. Broadcast transmission is not supported.
The Read Holding Registers query specifies the starting register and quantity of registers to be read. Note that registers are addressed starting at 0 (registers 1-16 are addressed as 0-15). The Read Holding Registers response message
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Model 932MB/934MB Modbus/RS485 Network I/O Modules
is packed as two bytes per register, with the binary contents right-justified in each byte. For each register, the first
byte contains the high order bits and the second byte the low order bits.
The following example reads holding registers 40006…40008 (Channel 0 high limit value, low limit value, deadband
value) at slave device 247:
Read Holding Register Example Query
Field Name
Example
Value (Hex)
Slave Address
247 (F7)
Function Code
3 (03)
Starting Address High Order
0 (00)
Starting Address Low Order
5 (05)
Number Of Points High Order
0 (00)
Number Of Points Low Order
3 (03)
Error Check (LRC or CRC)
--
Read Holding Register Example Response
Field Name
Example Value
(Hex)
Slave Address
247 (F7)
Function Code
3 (03)
Byte Count
6 (06)
Data High (Register 40006)
(3A)
Data Low (Register 40006)
75%=15000 (98)
Data High (Register 40007)
(13)
Data Low (Register 40007)
25%=5000 (88)
Data High (Register 40008)
(00)
Data Low (Register 40008)
1%=200 (C8)
Error Check (LRC or CRC)
--
To summarize, the contents of register 40006 (two bytes) is the channel 0 high limit of 75% (15000=3A98H). The
contents of register 40007 (two bytes) is the channel 0 low limit of 25% (5000=1388H). The contents of register
40008 is the channel 0 deadband value (two bytes) of 1% (200=00C8H).
Read Input Registers (04)
This command will read the binary contents of input registers (3x reference addresses) in the slave device. Broadcast
transmission is not supported.
The Read Input Registers query specifies the starting register and quantity of registers to be read. Note that registers
are addressed starting at 0--registers 1-16 are addressed as 0-15. The Read Input Registers response message is
packed as two bytes per register, with the binary contents right-justified in each byte. For each register, the first byte
contains the high order bits and the second byte the low order bits. The following example reads input registers
30003 & 30004 (Channel 0 input value and status) at slave device 247:
Read Input Register Example Query
Field Name
Example
Value (Hex)
Slave Address
247 (F7)
Function Code
4 (04)
Starting Address High Order
0 (00)
Starting Address Low Order
2 (02)
Number Of Points High Order
0 (00)
Number Of Points Low Order
2 (02)
Error Check (LRC or CRC)
--
Read Input Register Example Response
Field Name
Example Value
(Hex)
Slave Address
247 (F7)
Function Code
4 (04)
Byte Count
4 (04)
Data High (Register 30003) (3E)
Data Low (Register 30003) 80%=16000 (80)
Data High (Register 30004) (00)
Data Low (Register 30004) 136 (88)
Error Check (LRC or CRC) --
To summarize, the contents of register 30003 (two bytes) is the channel 1 input value of 80% (16000=3E80H). The
contents of register 30004 (two bytes) is the channel 0 status flags of 136 (0088H)-i.e. flagging high limit exceeded.
Force Single Coil (05)
This command will force a single coil/output (ox reference address) ON or OFF. For broadcast transmission, this
function forces the same coil in all networked slaves.
The Force Single Coil query specifies the coil reference address to be forced, and the state to force it to. The ON/
OFF state is indicated via a constant in the query data field. A value of FF00H forces the coil to be turned ON (i.e.
the corresponding solid-state relay is turned ON or closed), and 0000H forces the coil to be turned OFF (i.e. the solidstate output relay is turned OFF or opened). All other values are illegal and will not affect the coil. Note that coils are
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Model 932MB/934MB Modbus/RS485 Network I/O Modules
referenced starting at 0-up to 4 coils are addressed as 0-3 for this model and this corresponds to the discrete output
channel number. The following example forces discrete output 3 ON at slave device 247:
Force Single Coil Example Query
Field Name
Slave Address
Function Code
Coil Address High Order
Coil Address Low Order
Force Data High Order
Force Data Low Order
Error Check (LRC or CRC)
Force Single Coil Example Response
Example
Value (Hex)
247 (F7)
5 (05)
0 (00)
3 (03)
255 (FF)
0 (00)
--
Field Name
Slave Address
Function Code
Coil Address High Order
Coil Address Low Order
Force Data High Order
Force Data Low Order
Error Check (LRC or CRC)
Example
Value (Hex)
247 (F7)
5 (05)
0 (00)
3 (03)
255 (FF)
0 (00)
--
The Force Single Coil response message is an echo of the query as shown above, returned after executing the force
coil command. No response is returned to broadcast queries from a master device.
Preset Single Register (06)
This command will preset a single holding register (4x reference addresses) to a specific value. Broadcast transmission is supported by this command and will act to preset the same register in all networked slaves.
The Preset Single Register query specifies the register reference address to be preset, and the preset value. Note that
registers are addressed starting at 0--registers 1-16 are addressed as 0-15. The Preset Single Registers response message is an echo of the query, returned after the register contents have been preset. The following example writes a
baud rate of 9600bps to holding register 40002 (Baud Rate) at slave device 247:
Preset Holding Register Example Query
Field Name
Slave Address
Function Code
Register Address High Order
Register Address Low Order
Preset Data High Order
Preset Data Low Order
Error Check (LRC or CRC)
Preset Holding Register Example Response
Example
Value (Hex)
247 (F7)
6 (06)
0 (00)
1 (01)
0 (00)
2 (02)
--
Field Name
Slave Address
Function Code
Register Address High Order
Register Address Low Order
Preset Data High Order
Preset Data Low Order
Error Check (LRC or CRC)
Example
Value (Hex)
247 (F7)
6 (06)
0 (00)
1 (01)
0 (00)
2 (02)
--
The response simply echoes the query after the register contents have been preset. No response is returned to broadcast queries from a master device.
Force Multiple Coils (15)
This command will simultaneously force a sequence of coils (0x reference addresses) either ON or OFF. Broadcast
transmission is supported by this command and will act to force the same block of coils in all networked slaves.
The Force Multiple Coils query specifies the starting coil reference address to be forced, the number of coils, and the
force data to be written in ascending order. The ON/OFF states are specified by the contents in the query data field.
A logic 1 in a bit position of this field requests that the coil turn ON, while a logic 0 requests that the corresponding
coil be turned OFF. Unused bits in a data byte should be set to zero. Note that coils are referenced starting at 0-up to
4 coils are addressed as 0-3 for this model and this also corresponds to the discrete output channel number.
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Model 932MB/934MB Modbus/RS485 Network I/O Modules
The Force Multiple Coils normal response message returns the slave address, function code, starting address, and the
number of coils forced, after executing the force instruction. Note that it does not return the byte count or force value.
The following example forces outputs 1 & 3 OFF, and 0 & 2 ON for coils 0-3 at slave device 247:
Force Multiple Coils Example Query
Field Name
Example Value (Hex)
Slave Address
247 (F7)
Function Code
15 (0F)
Coil Address High Order
0 (00)
Coil Address Low Order
0 (00)
Number Of Coils High Order
0 (00)
Number Of Coils Low Order
4 (04)
Byte Count
01
Force Data High (First Byte)
5 (05)
Error Check (LRC or CRC)
-Note that the leading character of the 0x reference address is implied by the function code and omitted from the
address specified. In this example, the first address is 00001 corresponding to coil 0 and referenced via 0000H.
Thus, the data byte transmitted will address coils 3...0, with the least significant bit addressing the lowest coil in this
set as follows (note that the four unused upper bits of the data byte are set to zero):
Bin
Hex
Coil
0
0
0
0
0
1
0
NA
NA
0
1
1
0
5
NA
NA
3
2
Force Multiple Coils Example Response
Field Name
Example Value (Hex)
Slave Address
247 (F7)
Function Code
15 (0F)
Coil Address High Order
0 (00)
Coil Address Low Order
0 (00)
Number Of Coils High Order
0 (00)
Number Of Coils Low Order
4 (04)
Error Check (LRC or CRC)
-The normal response returns the slave address, function code, starting coil address, and quantity of coils forced, after
executing the force instruction. It does not return the byte count or force data. No response is returned to broadcast
queries from a master device.
Preset Multiple Registers (16)
This command will preset a block of holding registers (4x reference addresses) to specific values. Broadcast transmission is supported by this command and will act to preset the same block of registers in all networked slaves.
The Preset Multiple Registers query specifies the starting register reference address, the number of registers, and the
data to be written in ascending order. Note that registers are addressed starting at 0--registers 1-16 are addressed as 015. The Preset Multiple Registers normal response message returns the slave address, function code, starting register
reference, and the number of registers preset, after the register contents have been preset. Note that it does not echo
the preset values.
The following example writes a new slave address of 200, a baud rate of 28800bps, and sets parity to even, by writing
to holding registers 40001 through 40003 at slave device 247 (changes to slave address, baud rate, and parity will take
effect following the next software or power-on reset):
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Model 932MB/934MB Modbus/RS485 Network I/O Modules
Preset Multiple Registers Example Query
Field Name
Slave Address
Function Code
Starting Register High Order
Starting Register Low Order
Number Of Registers High Order
Number Of Registers Low Order
Preset Data High (First Register)
Preset Data Low (First Register)
Preset Data High (Second Reg)
Preset Data Low (Second Reg)
Preset Data High (Third Reg)
Preset Data Low (Third Reg)
Error Check (LRC or CRC)
Preset Multiple Registers Example Response
Example
Value (Hex)
247 (F7)
16 (10)
0 (00)
0 (00)
0 (00)
3 (03)
0 (00)
200 (C8)
0 (00)
5 (05)
0 (00)
2 (02)
--
Field Name
Slave Address
Function Code
Starting Register High Order
Starting Register Low Order
Number Of Registers High Order
Number Of Registers Low Order
Error Check (LRC or CRC)
Example
Value (Hex)
247 (F7)
16 (10)
0 (00)
0 (00)
0 (00)
3 (03)
--
The response simply echoes the query without returning the preset values after the register contents have been preset.
No response is returned to broadcast queries from a master device.
Report Slave ID (17)
This command returns the model number, serial number, and firmware number for a slave device, the status of the
Run indicator, and any other information specific to the device. This command does not address Register Map registers. Broadcast transmission is not supported.
The Report Slave ID query simply sends the slave address and function code with error check (CRC) as follows:
Report Slave ID Example Query
Field Name
Slave Address
Function Code
Error Check (LRC or CRC)
Example
Value (Hex)
247 (F7)
17 (11)
--
Report Slave ID Example Response
Field Name
Slave Address
Function Code
Byte Count
Slave ID
Run Indicator Status (ON)
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33
Example Value (Hex)
247 (F7)
17 (11)
26 (1A)
0 (00H) = 924MB-0900
1 (01H) = 913MB-0900
2 (02H) = 914MB-0900
3 (03H) = 917MB-0900
4 (04H) = 918MB-0900
5 (05H) = 901MB-0900
6 (06H) = 902MB-0900
7 (07H) = 903MB-0900
8 (08H) = 904MB-0900
9 (09H) = 905MB-0900
10 (0AH) = 906MB-0900
11 (0BH) = 932MB-0900
12 (0CH) = 934MB-0900
13 (0DH) = 942MB-0900
255 (FF)
Model 932MB/934MB Modbus/RS485 Network I/O Modules
Firmware Number ASCII
Byte String (Additional
Data Field)
Serial Number ASCII Byte
String (Unique Per Module)
Error Check (LRC or CRC)
"ACROMAG, 9300-041A,
934MB-0900,"(41 43 52 4F 4D
41 47 2C 39 33 30 30 2D 30 34
31 41 2C 39 33 34 4D 42 2D 30
39 30 30 2CH)
Six Numbers + Revision
"123456A"(31 32 33 34 35 36
41H)
--
The Report Slave ID response message returns the slave model ID and firmware number string as shown above.
Reset Slave (08)
This command is used to trigger a reset of the module and its effect is equivalent to a power-on reset of the module.
Note that changes to baud rate, slave address, and parity are initiated following reset. The Reset Slave command uses
sub-function 01 (Restart Communications) of the standard Modbus Diagnostics Command (08) to accomplish a module reset. This function does not operate on register map locations. Broadcast transmission is not supported.
The Reset Slave query simply sends the slave address, function code, sub-function code, and data (data is ignored and
simply echoed back), with error check (CRC). A Reset Slave response is simply an echoed acknowledge that is
returned just before the reset is executed. Allow a few seconds following reset to re-initiate communication with a
module.
Reset Slave Example Query
Field Name
Slave Address
Function Code
Sub-Function High Order Byte
Sub-Function Low Order Byte
Data Field High-Order Byte
Data Field Low Order Byte
Error Check (LRC or CRC)
Reset Slave Example Response (Sent Prior To Reset)
Example
Value (Hex)
247 (F7)
08 (08)
0 (00)
1 (01)
0 (00)
0 (00)
--
Field Name
Slave Address
Function Code
Sub-Function High Order Byte
Sub-Function Low Order Byte
Data Field High-Order Byte
Data Field Low Order Byte
Error Check (LRC or CRC)
Example Value
(Hex)
247 (F7)
08 (08)
0 (00)
1 (01)
0 (00)
0 (00)
--
Note that the response simply echoes the query just before the reset is triggered.
For Modbus software that does not support the Reset Slave function, an alternate method of generating a module reset
is provided via a write to the Calibration Access & Module Reset Register (See Register 40011 of Register Map).
Modbus Data Field
The data field of a message frame contains a multiple of 8 bits that provides the slave with any additional information
the slave requires to complete the action specified by the function code. The data field typically includes register
addresses, count values, and written data. The data field can be nonexistent for some commands (zero length), as not
all messages require data.
If no error occurs, the data field of a response from a slave will return the requested data. If an error occurs, the data
field returns an exception code (see Modbus Exceptions) that the master application can use to determine the next
action to take.
Supported Data Types
All I/O values are accessed via 16-bit Input Registers or 16-bit Holding Registers (see Register Map). Input registers
contain information that is read-only. For example, the current input value read from a channel, or the states of a
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Model 932MB/934MB Modbus/RS485 Network I/O Modules
group of digital inputs. Holding registers contain read/write information that may be configuration data or output
data. For example, the high limit value of an alarm function operating at an input, or an output value for an output
channel. I/O values for this model are represented by the following simple data types for temperature, percentage,
and discrete on/off.
Summary Of Data Types Used By DI-900MB Modules
Data Types
Description
Count Value A 16-bit signed integer value representing an A/D count, a DAC count, or a time value with a
range of -32768 to +32767.
Percentage
A 16-bit signed integer value with resolution of 0.005%/lsb. ±20000 is used to represent ±100%.
For example, -100%, 0% and +100% are represented by decimal values -20000, 0, and 20000,
respectively. The full range is -163.84% (-32768 decimal) to +163.835% (+32767 decimal).
Temperature A 16-bit signed integer value with resolution of 0.1°C/lsb. For example, a value of 12059 is
equivalent to 1205.9°C, a value of -187 equals -18.7°C. The maximum possible temperature
range is -3276.8°C to +3276.7°C.
Discrete
A discrete value is generally indicated by a single bit of a 16-bit word. The bit number/position
typically corresponds to the discrete channel number for this model. Unless otherwise defined for
outputs, a 1 bit means the corresponding output is closed or ON, a 0 bit means the output is open
or OFF. For inputs, a value of 1 means the input is in its high state (usually >> 0V), while a value
of 0 specifies the input is in its low state (near 0V).
Modbus Error Checking Fields
Modbus networks employ two methods of error checking: parity checking (even or odd parity, or none), and frame
checking (Cyclical Redundancy Check).
Parity Checking
A Modbus device can be configured for Even or Odd parity checking, or for no parity checking, and this determines
how the parity bit of the data frame is set.
If even or odd parity checking is selected, the number of 1 bits in the data portion of each character frame is counted.
Each character in RTU mode contains 8 bits. The parity bit will then be set to a 0 or a 1, to result in an even (Even
parity), or odd (Odd parity) total number of 1 bits. For example, if an RTU character frame contains the following
eight data bits: 1100 0011, then since the total number of 1 bits is 4 (already an even number), the frame's parity bit
will be 0 if even parity is selected. If odd parity is used, then the parity bit will be set to 1, making the total number of
bits an odd number (five).
When a message is transmitted, the parity bit is calculated and applied to the frame of each character transmitted. The
receiving device counts the quantity of 1 bits in the data portion of the frame and sets an error flag if the count differs
from that sent. As such, parity checking can only detect an error if an odd number of bits are picked up or dropped off
from a character frame during transmission. For example, if odd parity is employed and two 1 bits are dropped from
a character, the result is still an odd count of 1 bits. Note that all devices on a Modbus network must use the same
parity. If no parity checking is selected, then no parity bit is transmitted and no parity check is made. An additional
stop bit is transmitted to fill out the character frame for the no parity selection.
CRC Error Checking
RTU Mode message frames include an error checking method that is based on a Cyclical Redundancy Check (CRC).
The error checking field of a frame contains a 16-bit value (two 8-bit bytes) that contain the result of a Cyclical
Redundancy Check (CRC) calculation performed on the message contents. The CRC value is calculated by the transmitting device and is appended to the message as the last field in a message-the low order byte is appended first, followed by the high-order byte. Thus, the CRC high-order byte is the last byte to be sent in a message. The receiving
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Model 932MB/934MB Modbus/RS485 Network I/O Modules
device calculates a CRC during receipt of a message and compares the calculated value to that received in the CRC
field. If the two values differ, an error results.
The CRC is started by first preloading the 16-bit CRC register to all 1’s. Successive 8-bit bytes of the message (only
the 8-data bits in each character--no start, stop, or parity bits) are applied to the current contents of the register, and
each 8-bit character is exclusive OR’ed with the register contents. The exclusive OR result is shifted in the direction
of the least significant bit (lsb) of the CRC, with a zero placed into the most significant bit (msb). The lsb is then
extracted and examined, if the lsb is a 1, the register is exclusive OR’ed with a preset fixed value. If the lsb is a 0, no
exclusive OR takes place. This process is repeated until 8 shifts have been performed. After the last (eighth) shift,
the next 8-bit byte is exclusive OR’ed with the register’s current contents, and the process repeats itself for 8 more
shifts as described above. The final contents of the CRC register after all the message bytes have been applied is the
CRC value.
Modbus Exceptions
If an unsupported function code is sent to a module, then the exception code 01 (Illegal Function) will be returned in
the data field of the response message. If a holding register is written with an invalid value, then exception code 03
(Illegal Data Value) will be returned in the response message. The following table lists possible exception codes:
Modbus Exception Codes
Code
Exception
01
Illegal Function
02
Illegal Data Address
03
Illegal Data Value
04
Slave Device Failure
05
Acknowledge
06
Slave Device Busy
07
Negative Acknowledge
08
Memory Parity Error
Description
The function code received in the query is not allowed or invalid.
The data address received in the query is not an allowable address for the
slave or is invalid.
A value contained in the query data field is not an allowable value for the
slave or is invalid.
An unrecoverable error occurred while the slave was attempting to perform the requested action.
The slave has accepted the request and is processing it, but a long duration of time is required to do so. This response is returned to prevent a
timeout error from occurring in the master.
The slave is engaged in processing a long-duration program command.
The master should retransmit the message later when the slave is free.
The slave cannot perform the program function received in the query.
This code is returned for an unsuccessful programming request using
function code 13 or 14 (codes not supported by this model). The master
should request diagnostic information from the slave.
The slave attempted to read extended memory, but detected a parity error
in memory. The master can retry the request, but service may be required
at the slave device.
In a normal response, the slave echoes the function code of the original query in the function field of the response.
All function codes have their most-significant bit (msb) set to 0 (their values are below 80H). In an exception
response, the slave sets the msb of the function code to 1 in the returned response (i.e. exactly 80H higher than normal) and returns the exception code in the data field. This is used by the master's application to recognize an exception response and to direct an examination of the data field for the applicable exception code.
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Model 932MB/934MB Modbus/RS485 Network I/O Modules
6. Module Software Configuration
From the factory, each module has a default configuration as detailed in the Module Installation section of this manual. Your application will likely differ from the default configuration and the module will need to be reconfigured.
Series DI-900MB modules may be configured and calibrated by issuing the appropriate Modbus functions to the Register Map registers, as required to configure the unit. However, it is much simpler to use the DI-900MB Configuration Software to program and control the module parameters and operating modes. This software is easy to use, selfexplanatory, and complete configuration takes only a few minutes. On-line help is built-in. As such, a comprehensive guide to the use of this program is not necessary. To begin configuration, you should already be familiar with
Windows operation and have a basic understanding of module terminology as it relates to this model.
Before You Begin
1.
Have you installed the DI-900MB Configuration Program? You should complete the Module Installation section
of this manual before proceeding.
2.
Check that all necessary electrical connections have been made and that power is applied (module's green LED
ON).
3.
Is baud set correctly at the RS485 converter/repeater??
4.
Have you tried communicating using the Default Mode? Press the “DFT” push-button of the module until the
yellow status LED is flashing. This sets the module's communication parameters to 9600 baud, a slave address
of 247, no parity, and two stop bits.
5.
If you fail to communicate with the module or have a high degree of communication errors, try increasing the
response delay time (See Response Delay Register 40006). Some network converters or host/software systems
cannot accept an immediate response from a slave without added delay.
The following sections guide you through the Configuration Program property sheets used to configure a DI-932MB
or DI-934MB Transmitter. These models share identical circuits and only differ in the number of input channels.
Property sheets will vary from model to model, but the general approach is the same.
Module Software Configuration
37
Model 932MB/934MB Modbus/RS485 Network I/O Modules
Starting The Program
After clicking on the Series DI-900MB program icon to boot the Configuration Program,
a screen will be displayed similar to that
shown at right.
To begin, click on the “Settings-Serial Communications…” pull-down menu (or press
Ctrl-E) to set the COM port, baud rate, parity,
and slave address that the host computer will
use to communicate with the module (as
shown at right). Optionally, you can check the
“Update Communications settings at download” box to automatically change the host settings to match the module if new settings are
later downloaded to the module (recommended to conveniently maintain communication with a module following reconfiguration).
Note that the host COM port selected is indicated in the first box of the lower right-hand corner. MODULE is indicated in the third box if a connected module is detected by the software. The fourth and fifth boxes indicate NUM for
Num lock and CAP for Caps lock, respectively. Available menu selections are listed below.
File
New...
Open...
Save
Save As...
Print...
Print Preview
Print Setup...
Recent File Indicated
Exit
Use File-New to create a new configuration file. You will be prompted to select a model number. Use File-Open to
open an existing configuration file.
Use File-Save to save the current configuration file to disk. Use File-Save As to save the current configuration file to
a new file name.
Use File-Print to get a printout of the currently loaded configuration file. Use File-Print Preview to view the current configuration or preview the print documentation. Use File-Print-Setup to select a printer and font style.
Module
Upload Configuration
Download Configuration
Use Module-Upload Configuration to upload the module’s current configuration and calibration.
Use Module-Download Configuration to write the currently loaded configuration to the module.
Settings
Serial Communications...
Communications Port
Host Baud Rate
Host Parity
Slave Address
Module Software Configuration
38
Model 932MB/934MB Modbus/RS485 Network I/O Modules
Use the Communications Port Scroll Window to select the host COM port the module is connected to (COM1COM4), or type in a COM port as required, from COM1 to COM99. The selected COM port is indicated in the lower
right-hand corner of the screen.
Use the Baud Rate scroll window to select the baud rate to be used by the host in communicating with the module.
Use the Parity scroll window to select Odd, Even, or No Parity checking by the software for data transfer.
Use the Slave Address scroll window to tell the software which module to address.
If you wish to maintain communications with a module following download, you should check the “Update Communications settings at download” box of the Settings window to keep the host in synch with a module if the module settings are changed.
If the module is in the Default Mode (indicated via a flashing status LED), the baud rate, address, and parity assumed
by the module are fixed at 9600bps, 247, and No Parity. You must use the same settings as the connected module.
Help
Configuration Help Topics
Your Model Help Topics
About Modbus Configuration
About Your Model
Use Help to obtain information about using this software or configuring transmitters. Note that context sensitive help
(?) is also available for help on a specific field or topic. Simply click on the [?] button, then click on the field or topic
of interest to obtain help on that subject. You may also click the right mouse button to copy or print the help screen
while it is being displayed.
The following sections review the configuration of a Model DI-934MB transmitter. The Model DI-932MB is configured in the same manner, but has two less input channels.
Creating A Configuration File
You may use File-New to create a new configuration file, or File-Open to open an existing
configuration file. However, It is recommended that you first use Module-Upload
Configuration to retrieve the current active
configuration from the connected module.
This will automatically detect the correct
model number and load the property sheets for
that model.
Once you create, open, or upload a configuration file, a screen similar to the one shown at
right will be displayed. Your screen will vary
according to your model number. The model
number is indicated at the top of the screen
along with the current file name. The Model
DI-934MB General screen is shown here.
Note that 5 property sheets define this transmitter's configuration: General, Configure Alarms 0 & 1, Configure
Alarms 2 & 3, Test, and Input Calibration.
Module
The Serial and Firmware numbers are indicated at the top of the General screen and cannot be modified.
For “Tag:”, enter up to 15 alphanumeric characters (optional).
Module Software Configuration
39
Model 932MB/934MB Modbus/RS485 Network I/O Modules
For “Comment:”, enter up to 31 alphanumeric characters (optional).
For “Configured By:”, enter your name up to 15 alphanumeric characters (optional).
You can also add a “Location:” note of up to 25 alphanumeric characters (optional).
For “Channel ID:” (bottom), enter up to 15 alphanumeric characters of identification information relative to the output channel (optional).
Use the “Slave Address” scroll bar to select a new module address that will take effect following download. Select
from 1 to 247. Address 247 is reserved for Default Mode.
Use the “Baud Rate” scroll bar to select a new baud rate to be used by the module following download. Select 2400,
4800, 9600 (Default Mode), 14400, 19200, 28800, 38400, 57600, 76800, or 115200 bits per second.
Use the “Parity” scroll bar to select Odd, Even, or No Parity (Default Mode) error checking by the module.
Note that slave address, baud rate, and parity selections take effect following a configuration download and do not
alter the settings used by the host software (configured separately via the Settings menu).
If you checked the “Update Communications settings at download” box of the Settings pull-down menu, the host
software will change its own settings to match the module settings that take effect following a download in an effort
to maintain communication with the module. Otherwise, you must change the host Settings separately after downloading to match the new module settings. If the module is in Default Mode (indicated via a flashing status LED), the
baud rate, address, & parity of the module are fixed at 9600bps, 247, and No Parity.
Use the “Range:” scroll bar to pick one of the following ranges according to your model (Model DI-924MB ranges
shown):
Pt 100Ω (1.3850) -200 to 850°C
Pt 100Ω (1.3911) -200 to 850°C
Ni 120Ω (1.6720) - 80 to 320°C
Cu 10Ω (1.4272) -200 to 260°C
Resistance 0-500Ω (% of span)
Note that RTD inputs return units of °C, while resistance inputs returns units of percent-of-span. For the 0-500Ω
range, a 0% indication represents 0W, and 100% represents 500Ω. Scaling of ±20000 to ±100% is done for convenience of display in this software.
Your software may rescale these values as required for your application. Keep this in mind when using other software to communicate with the module.
Multiple inputs of the same module must have same input type. All input ranges have already been factory calibrated.
To begin configuring your module, start by selecting an input range as required.
Click on “RTD Wiring” to select a 2-Wire or 3-Wire configuration (RTD only).
Click on “Temp Units” to select °C, °F, or K (Kelvin) units of measure for the input signal (RTD inputs only).
IMPORTANT: The module returns units in °C only. The selection of °F or K only applies to their use within this
software.
Changing units will cause alarm levels already set to revert to their range endpoints.
For “Sensor Break,” select Upscale or Downscale break detection for all inputs. Break detect will result in an
upscale or downscale range endpoint reading and the module's ST LED to turn ON.
Use the “Response Delay” field to specify a delay from 0 to 65500 ticks with 1 tick equal to 1.085 microseconds.
Response delay is the added turnaround delay applied between message receipt by the module and its response to the
host. A fixed amount of delay is already present and varies with the model. Thus, you will have to specify a comparably greater amount of response delay to measure any affect. Some host software or signal converters require added
delay to work properly.
Module Software Configuration
40
Model 932MB/934MB Modbus/RS485 Network I/O Modules
If you wish to enable the I/O Watchdog Timer, specify a “Watchdog Timeout” delay from 1 to 65534 seconds (0
will disable timer). A watchdog timeout will occur if no I/O has occurred within this time period.
You may click the “Watchdog Reset” check box to also send the outputs to their reset states upon watchdog timeout
(Reset States are set via the Configure Alarms screens).
The next section covers optional alarm configuration.
Alarm Configuration
Clicking the Configure Alarms property sheet
tab(s) will display a screen similar to the one
at right. A second Configure Alarms 2 & 3
screen is included for four channel DI-934MB
models. Your screen may vary slightly
according to your model and selected input
range.
IMPORTANT: Limit checking is always
active, while alarm outputs are enabled selectively. Default limit values are the input range
endpoints.
The default High and/or Low Limit values can
be changed. You can enable the corresponding output as an alarm output via the High/
Low Alarm Output Enable boxes. You can
also specify failsafe or non-failsafe alarm outputs. Optionally, deadband may be applied to a limit. Refer to the limit
alarm configuration field descriptions below to complete this information for Limit Alarms 0 & 1, and 2 & 3 (DI934MB).
Alarm Config Field Descriptions
Limit Alarm (Each Input)
Hi/Lo Alarm Output En (Each Input): Enable High and/or Low Limit alarm output control for each input. Limit
alarm control of the corresponding output takes priority over direct control when enabled.
High Limit (Each Input): The high limit level is programmable over the entire input range and entered in the same
engineering units as the input. The corresponding alarm output will go to its alarm state for an increasing input signal
that equals or exceeds the high limit value (if enabled).
Low Limit (Each Input): The low limit level is programmable over the entire input range and entered in the same
engineering units as the input. The corresponding alarm output will go to its alarm state for a decreasing input signal
that equals or goes below the low limit value (if enabled).
Deadband (Each Input): Deadband may be applied to both limit levels and is programmable over the entire input
range. Deadband is entered in the same units as the input and determines the amount the input signal has to return
into the “normal” operating range before the corresponding alarm relay will transfer out of the “alarm” state. Deadband is normally used to eliminate false trips or switch “chatter” caused by fluctuations of the input near the limit.
Alarm Mode (Each Input): This field allows you to select failsafe or non-failsafe alarm output activation. Alarm
outputs must be separately enabled. A failsafe alarm output will turn OFF in alarm (the same state as the powerdown state). A non-failsafe alarm output will turn ON in alarm.
Alarm control of the output will take precedence over direct control when the High/Low Alarm Output Enable box is
checked. Keep this in mind if you attempt to control the state of an alarm output directly, as the module will seek to
maintain the correct output state relative to the alarm condition and alarm mode, each time it scans the input. How-
Module Software Configuration
41
Model 932MB/934MB Modbus/RS485 Network I/O Modules
ever, this does not apply for input signals within the deadband region. If the input is within the deadband region, the
discrete output state can be controlled directly, but direct control of an alarm output is not recommended.
There are three methods of detecting an alarm: the output status LED can be used to indicate a transfer to the alarm
state, a global limit exceeded flag will be set in the Module Status Register, and a high and/or low limit flag will be
set in the Channel Status Register. The Test Page of this software program will also report the alarm status for the
module and an input channel.
Watchdog Output Reset Value: This selection determines the state the output will be automatically toggled to following a watchdog timeout. Select “On” or “Off” as required. Watchdog timer control of an output will take precedence over alarm and direct control.
Writing Your Configuration
After making your General and Alarm Configuration selections, you must download the new settings as follows:
Select Module-Download Configuration to write your configuration to the module.
Module
Upload Configuration
Download Configuration
Note that you can select Module-Upload Configuration to retrieve the module's current alarm configuration and calibration, or to review and verify its configuration. Configuration data is stored in non-volatile memory within the DI900MB module.
The next section covers testing of your configuration. If you have made changes to any of the module configuration
screens, be sure to down-load your changes to the module prior to invoking any of the test or calibration pages.
Testing Your Configuration
The “Test” portion of this program allows you
to monitor polling, module status flags, read
input values, reset the module, and control or
monitor outputs.
CAUTION: If you have made changes to
module configuration data screens but have
not already downloaded those changes to the
module, then selecting this page may change
some of your software selections to match
those obtained from polling the module.
Always download your changes to the module
before invoking the Test or Cal pages.
Test Operation
Click on the “Test” property sheet tab to test
the configuration just written to your module and a screen similar to the one at the right will be displayed (A Model
DI-934MB Test screen is shown).
The flashing green Status lamp next to “Polling Status” indicates the software is communicating with the module and
polling its I/O. Polling is automatic when this screen is displayed and turns off if another screen is selected. Note that
a watchdog timeout will never occur if you are viewing this screen as it continuously polls the I/O.
The graphic simulation of the module LED's reflect the current LED status of the module.
You can reset the module by clicking the “Reset” button (same effect as power-on reset). Note that a module will exit
the Default Mode following a reset. New address, baud rate, and parity settings will take effect immediately following a reset-to continue communications following reset, make host software adjustments accordingly via the Settings
pull-down menu.
Module Software Configuration
42
Model 932MB/934MB Modbus/RS485 Network I/O Modules
For each input, the current selected input range, input value (“Value:”), and input status is indicated (under-range,
OK, limit exceeded, or over range). The output states are also indicated. You may also turn the outputs On/Off by
clicking on the Output On or Output Off buttons (assuming outputs are not already enabled as alarm outputs). Keep
in mind that alarm control of an output has priority over direct control (if enabled) and will seek to maintain the correct output state relative to the input level each time the input is scanned.
Clearing a watchdog timeout by initiating I/O with a module that has timed out will not automatically return the digital outputs to their pre-timeout state. It simply returns control of the output state to the alarms, or to the operator via
manual control. Watchdog timeout control of the output has the highest priority (if enabled), followed by alarms (if
enabled), with manual control of the outputs having the lowest priority.
If an output is already enabled as an alarm output, then alarm control of the output state will over-ride manual control
of the output state.
NOTE: The resistance input will always return its measurements in scaled percent-of-span units with ±20000 representing ±100%. Scaling to input signal engineering units is done via this software for the convenience of display.
Likewise, RTD inputs always return their measurements in °C, with translation to °F or K done for convenience via
this software. Keep this in mind when using other software packages to interrogate a module.
Print Your Configuration
If you wish to document your transmitter configuration, then select File-Print to get a two page printout of all of your
selected configuration parameters.
Saving Your Configuration
You should select File-Save As to save your configuration file to disk and give it a new file name.
Use File-Save to save the current file without renaming it.
Note that the currently loaded configuration file name is indicated at the top of the screen to the right of the model
number. In the event that you lose a configuration file, you can always upload it from the module via Module-Upload
Configuration.
Now wasn't that easy! That's all there is to using the Configuration software to configure your module. The module
is now ready for installation in the field.
Note that the configuration process will vary slightly for other model types. The next section covers calibration of
your inputs. Note that calibration has already been done at the factory and adjustment is not generally required.
However, periodic recalibration may be performed to correct for component aging, or as part of your company's
maintenance requirements.
Module Calibration
Calibration of a module is much simpler using
the controls of the Modbus Configuration
Software as described here.
CAUTION: If you have made changes to
module configuration data screens but have
not already downloaded those changes to the
module, then selecting this page may change
your software selections to match those
obtained from polling the module. Always
download accumulated changes to a module
before invoking the Test or Input Cal pages to
prevent data loss.
Module Software Configuration
43
Model 932MB/934MB Modbus/RS485 Network I/O Modules
Note: Calibration of all supported input ranges has already been done on your module at the factory. Recalibration is
normally not required, except as necessary to correct for long term component aging or to satisfy your company's
maintenance requirements.
This portion of the program will allow you to calibrate the nominal input ranges of your module.
WARNING: Miscalibration may render an input channel unstable or inoperable. Try recalibrating an input if it
appears unstable.
For best results, you will need a precision input resistance source capable of reproducing nominal RTD input range
endpoint signals, at least as accurate as the module itself. You will also need an RTD table that relates RTD resistance
to temperature.
Prior to calibration, configure the RTD wiring as desired in your final application (2-Wire or 3-Wire) and allow the
module to warmup a few minutes.
Module Input Calibration
1.
Click on the Input Calibration property sheet tab to display the screen shown at right (your screen may be slightly
different according to your model and selected input range).
Note that Module-Upload Configuration will recall the module's current calibration for review or to make minor
adjustments.
After upload, the current Low and High calibration values will be indicated in the Calibration Value fields.
These correspond to the nominal input range endpoint signals of the selected input range. Uploading first will
help prevent miscalibration if the input range set at the module is different than that selected via this software.
2.
Adjust your input resistance to precisely match that of the Low Calibration Value field entry.
3.
If the current input value indicated in the “Value:” field does not precisely match the low input signal value, and
the externally applied low endpoint signal level, press the Low “Calibrate” button to set the Low Calibration
Value. After a moment, the value indicated should match the Low Calibration Value.
4.
Next, adjust your input resistance to precisely match the High Calibration Value field entry. Observe proper
polarity.
5.
If the current input value indicated in the “Value:” field does not precisely match the high input signal value and
the externally applied high endpoint signal level, press the High “Calibrate” button to reset the High Calibration
Value. After a moment, the value indicated should match the High Calibration Value.
6.
Repeat steps 1-5 for each of the other input channels, as required.
Please Note:
Calibration points are restricted to the current selected input range endpoint values. Be sure to precisely match these
levels via your resistance source. Failure to use calibration points other than the current input range endpoints will
result in measurement error.
For best results, wire the RTD as required by the final application (2-wire or 3-wire connection) and allow the module
to warmup a few minutes prior to calibration. In addition, you should always calibrate the low value first before the
high value.
Resistance input always returns measurements in scaled percent-of-span units with ±20000 representing ±100%.
Scaling to input signal engineering units is done via this software for the convenience of display. Likewise, RTD
inputs always return measurements in °C. Translation to °F or K is done for convenience via this software. Keep this
in mind when using other software packages to interrogate a module.
Refer to Drawing 4501-895 at the back of this manual for example input connections.
Module Software Configuration
44
Model 932MB/934MB Modbus/RS485 Network I/O Modules
7. Block Diagrams and Schematics
Theory of Operation
Refer to Simplified Schematic 4501-893 and Functional Block Diagram 4501-894 to gain a better understanding of
the circuit. Note that these transmitters will process up to two or four RTD input signals, and provide network commands to configure the module, monitor the inputs, and control the outputs. An integrated multiplexer and analog
switch are used to connect each of two input channels to an A/D converter. The A/D converter then applies appropriate gain to the signal, performs analog-to-digital conversion, and digitally filters the signal. The digitized A/D signal
is then transmitted to a microcontroller. The microcontroller completes the transfer function according to the input
type and its embedded program. The microcontroller also compares the signal value to the limit value if the alarm
function is used and completes all necessary alarm functionality per its embedded program. I/O lines of the microcontroller also switch the solid-state relays ON/OFF, as required. The UART of the microcontroller sends/receives its
I/O signals to the network via an optically isolated RS485 transceiver. Embedded configuration and calibration
parameters are stored in non-volatile memory integrated within the micro-controller. New module functionality can
be downloaded via the host running the Modbus Configuration Software, or other compatible Modbus software along
the network. A wide input switching regulator (isolated flyback mode) provides isolated power to the various I/O circuits. Refer to Functional Block Diagram 4501-894 for an overview of how the software configuration variables are
arranged.
Simplified Schematic (4501-893)
ISOLATED INPUT
INPUT POWER
MODEL 932/934MB-0900
DUAL/QUAD RTD INPUT
WITH ISOLATED RS485 OUTPUT
OUTPUT/
ALARM
STATUS
CH0
PWR LED
CH1
STATUS LED
934MB
ONLY
CH2
CH3
+5V
REG
+5V
+5V
ISOLATED POWER
+6V
10-36V DC
24VAC
POWER ISOLATED
FLYBACK
PWR
+5V
REG
ISOLATED RS485 PORT
+5V
+5V
COM
1+
3
1R+
A/D CONV #1
OPTICAL
ISOLATION
2-
D
RS485
TRANSCEIVER
RS485
D
MICRO
CONTROLLER
2+
1+
ISOLATED DIGITAL OUTPUTS (SOLID-STATE RELAYS)
1R+
A/D CONV #2
(934MB ONLY)
OUT0 (+)
2-
RTN (-)
2+
OUT1 (+)
LRTN
OUT2 (+)
PUSH FOR DEFAULT
MODE - STATUS LED
FLASHES
OUT3 (+)
RTN (-)
934MB
ONLY
DEFAULT MODE
SWITCH
4501-893A
Block Diagrams and Schematics
45
Model 932MB/934MB Modbus/RS485 Network I/O Modules
Functional Block Diagram (4501-894)
Limit and Deadband
(Full Sensor Input Range)
Via Configuration Software
MODEL: 932MB-0900 & 934MB-0900
RTD TO MODBUS TRANSMITTER
FUNCTIONAL BLOCK DIAGRAM
Configuration Variables:
High and/or Low Limits
Analog INPUT Type/Range:
Pt 100 OHM (1.3850)
Pt 100 OHM (1.3911)
Ni (1.6720)
Cu 10 OHM (1.4272)
Resistance (0-500 OHM)
Alarm
SOLID-STATE RELAY (SSR) OUTPUT
RATED TO 48VDC, 1A (ONE PER
INPUT) WITH COMMON RETURN
ON/OFF
Alarm
LIMIT ALARM
On/Off
SPST-NO
Alarm
PV
NOTE: Alarm control
of Output SSR takes
precedence over direct
control. I/O Watchdog
Timeout Control Has
Highest Precedence.
DIGITAL
OUTPUT
BLOCK
LIMIT/
DEADBAND
BLOCK
1+
1-
Input Sensor Types:
RTD (2 & 3-Wire)
Resistance
REF
2-
A/D
#1
2+
1+
ANALOG INPUTS 2,3
(934MB-0900 ONLY)
A/D
#2
1-
Input Sensor Types:
RTD (2 & 3-Wire)
Resistance
A/D
CONVERTERS
Counts
PV
ANALOG INPUTS 0,1
PV
Counts
Registers
RS485
Modbus
Counts
SENSOR
INPUT BLOCK
REF
REGISTERS
MODBUS
PROTOCOL
BLOCK
2-
ISOLATED
NETWORK
INTERFACE
2+
4501-894A
Network Connections (4501-805)
PERSONAL COMPUTER
W / W INDOW S 95/98 OR NT
PC RUNNING
ACROMAG
MODBUS CONFIG
SOFTW ARE
SERIES 9XXMB NETW ORK CONNECTIONS
SET BAUD RATE, PARITY
RS232
PORT
OPTIONAL 120 OHM
TERMINATION RESISTOR
NOTE: RS485 PORT COMMON
SHOULD CONNECT TO EARTH
GROUND AT ONE POINT.
RS485 NETW ORK - HALF DUPLEX
COMRx Tx
CONNECT
COM D D POW ER
CONNECT
COM D D POW ER
CONNECT TO AC POW ER
A
C
IN
P
UT
TO ADDITIONAL
MODULES OR
OTHER RS485
NETW ORK DEVICE
D D
C
R O Rx Tx
S- M
TB23
1 2C
T
R R
STB48
2 5
T
R D
D
COM
24
24
C
V RT V
O
D N D
M
C
C
TB4
46 OU
45 OU
44 RT
43 OU
42 OU
41
TB RT
T3 T2 N T1 T0
4 N
TB4
TB3
TB
46 CH
45 CH
43 CH
42 EX
41 4
44 CH
RT
11 10 9 8 C3
N
36 35
CO 34 33 32 31
TB CO
3 M M D D B A
RS485
DIGITAL OUTPUTS
PW R
DIGITAL I/O
SET BAUD RATE, PARITY, ADDRESS
TB
1
CJC-0 IN0
INPUTS
0,1
IN0 IN1 IN1
+ - + -
TB
2
11 12 13 14 15 16
POW ER
1 - 300 5 - 4800
2 - 600 6 - 9600
3 - 600 7 - 19.2K
4 - 2400 8 - 38.4K
RS 485
PW R
MODEL 906MB-0900
MODEL 924MB-0900
ANY RS232-TO-RS485 CONVERTER
TB3
TB
36 CO
35 34 33 32 31 3
CO
M M D D
CJC-1 IN2
INPUTS
2,3
IN2 IN3 IN3
+ - + -
SET BAUD RATE, PARITY, ADDRESS
TB
1
21 22 23 24 25 26
EX
DIGITAL
orCH
OUT
CH CHINCH
RT
C1 0 1 2 3 N
TB
2
11 12 13 14 15 16
EX
DIGITAL
orCH
OUT
CH CHINCH
RT
C2 4 5 6 7 N
21 22 23 24 25 26
1 2 3 4 5 6 7 8
BAUD
RATE
S1
232 >
485
RS485
FAULT
485 >
232
TB1
TB2
TB1
TB2
SET BAUD RATE
4501-805A
Block Diagrams and Schematics
46
Model 932MB/934MB Modbus/RS485 Network I/O Modules
Electrical Connections (4501-895)
ELECTRICAL CONNECTIONS
MODEL 932MB-0900 AND 934MB-0900
NOTE 2: RETURNS SHOULD BE CONNECTED TO EARTH GROUND
AT THE SAME POINT TO AVOID CIRCULATING GROUND CURRENTS.
INPUT CONNECTIONS
NOTE 3: RS485 PORT COMMON SHOULD CONNECT TO EARTH
GROUND AT SOME POINT ALONG THE NETW ORK.
3-W IRE RTD
DIGITAL I/O
TB1/TB2
TB1/TB2
RESISTANCE
DECADE BOX
IN+
ININL
(SEE I/O CONNECTIONS AT LEFT)
INTB4
RUN
ST
UNUSED INPUTS
TB1/TB2
R
TB1/TB2
IN+
IN- JUMPER [IN-] TO [INL]
INL FOR 2-W IRE RTD
ININL
R
JUMP
0
1
2
3
IN+
NOTE 1
RUN/PW R LED (GREEN)
STATUS LED (YELLOW )
DEFAULT MODE SW ITCH PUSH FOR DEFAULT MODE.
STATUS LED FLASHES IN
DEFAULT MODE.
STATUS LED W ILL FLASH
RAPIDLY UPON W ATCHDOG
TIMEOUT.
OU 45 OU
44 OU
43 42 OU
41
TB 46 RT
RT
T3
T2 T1
T0
4
N
N
OUTPUT LED (YELLOW ) ON W HEN OUTPUTS ARE
CONDUCTING.
R
D
0-48V
L
SHIELDED CABLE
R
TB1
REMOVABLE
(PLUG-IN TYPE)
TERMINAL BLOCKS
21 22 23 24 25 26
TB1
TB2
OUT0
RTN
OUT1
L
OUT1
OUT2
OUT2
RTN
(+)
V
A
11 12 13 14 15 16
FOUR SOLID-STATE RELAY
OUTPUTS W ITH A COMMON
RETURN AND RATED TO
48VDC, 1A.
OUT0
934MB Only
RTD INPUTS 2,3
TB IN2 IN2 IN2 IN3 IN3IN3
2 + - L + - L
932MB/934MB
RTD INPUTS 0,1
TB IN0 IN0IN0 IN1 IN1IN1
1 + - L + - L
IMPORTANT: RTD INPUTS ARE NOT
ISOLATED CHANNEL TO CHANNEL
POSSIBLE VARIATIONS - DC APPLICATIONS ONLY
D
PWR
INL
DIGITAL OUTPUT CONNECTIONS
0-48V
RS485
DIGITAL OUTPUTS
TERMINATE UNUSED
INPUT CHANNELS
V
B
LR 35 34 33 32 31
TB 36 CO
TN M D D B A
3
IN-
EARTH
GROUND
DO NOT
GROUND
DFT
IN+
TB3
TB4
DATAQ
2-W IRE RTD
10 TO 36VDC
OR 24VAC
NON-POLARIZED
INL
JUMP
EARTH
GROUND
DC/AC
POW ER
IN+
JUMPER [IN-] TO [INL] FOR
RESISTANCE BOX OR 2-W IRE
NOTE 1
DO NOT
GROUND
NE
(S
TW
EE
OR
DR
K
AW
CO
IN
NN
G
EC
45
TI
01ON
80
S
5)
NOTE 1: DO NOT APPLY EARTH GROUND TO INPUT LEADS OR INPUT
TERMINALS. EARTH GROUND SHOULD INSTEAD BE APPLIED AT THE
INPUT LOGIC RETURN TERMINAL (LRTN AT TB3-36).
0 to V B
OUT3
(-)
SHIELDED
CABLE
W ARNING: FOR COMPLIANCE TO APPLICABLE SAFETY AND
PERFORMANCE STANDARDS, THE USE OF SHIELDED CABLE IS
RECOMMENDED AS SHOW N. ADDITIONALLY, THE APPLICATION
OF EARTH GROUND MUST BE IN PLACE AS SHOW N IN THIS
DRAW ING. FAILURE TO ADHERE TO SOUND W IRING AND
GROUNDING PRACTICES MAY COMPROMISE SAFETY AND
PERFORMANCE.
RTD INPUT CONNECTIONS
(SEE INPUT CONNECTIONS AT LEFT)
SAFETY GUIDELINES MAY REQUIRE THAT THIS DEVICE BE
HOUSED IN AN APPROVED METAL ENCLOSURE OR SUBSYSTEM, PARTICULARLY FORAPPLICATIONS W ITH VOLTAGES
GREATER THAN OR EQUAL TO 75VDC/50VAC.
EARTH GROUND
(SEE NOTE 2)
FOR DC-POW ERED INTERPOSING RELAY
CONNECTIONS SEE DRAW ING 4501-896
4501-895A
Interposing Relay Conn. & Contact Pro. (4501-896)
NETWORK CONNECTIONS
(SEE DRAWING 4501-805)
INTERPOSING RELAY CONNECTIONS
MODEL 932MB-0900 AND 934MB-0900
DIGITAL I/O
CONTACT PROTECTION
1N4006 OR EQUIVALENT
(SEE NOTE 2)
1
+
-
2
3
RS485
A
B
D
D
TB3
COM
LRTN
RTN
OUT0
RTN
EARTH
GROUND
36 35 34 33 32 31
DIGITAL OUTPUTS
PWR
OUT0 (SPST-NO)
RTN
OUT1
OUT2
RTN
NOTE 1: RETURNS SHOULD BE CONNECTED TO EARTH GROUND
AT THE SAME POINT TO AVOID CIRCULATING GROUND CURRENTS.
NOTE 2: DIODE ADDED LOCAL TO INDUCTIVE LOAD TO SHUNT THE
REVERSE EMF THAT IS GENERATED WHEN CURRENT THROUGH
THE INDUCTOR (RELAY COIL) IS TURNED OFF.
EARTH GROUND
(SEE NOTE 1)
IN3-
IN3L
IN3+
TB2
IN2+
11 12 13 14 15 16
IN2L
RTD INPUTS 2,3
IN1L
IN1-
IN1+
IN0L
RTD INPUTS 0,1
OUTPUTS INCLUDE
TRANSIENT AND
REVERSE SHUNT
PROTECTION
IN2-
OUT3
EARTH GROUND
(SEE NOTE 1)
IN0-
TYPICAL DIN-RAIL MOUNTED RELAY IN
DE-ENERGIZED CONDITION.
NOTE: ALL RELAY CONTACTS SHOWN.
TB3
46 45 44 43 42 41
TB1
IN0+
4
DIODE
FOUR SOLID-STATE
OUTPUT SWITCHES
WITH COMMON RETURN
SHIELDED CABLE RATED TO 48VDC AND 1A
OUT1
0-48V DC
8
5
+
OUT2
IMPORTANT - OBSERVE PROPER POLARITY
6
7
DC RELAY
POWER
10 TO 36VDC
OR 24VAC
NON-POLARIZED
TB4
TB4
OUT3
LOCATE RELAY NEAR LOAD
DC/AC
POWER
21 22 23 24 25 26
TB1
TB2
SHIELDED CABLE
RTD INPUT CONNECTIONS
(SEE DRAWING 4501-895)
4501-896A
Block Diagrams and Schematics
47
Model 932MB/934MB Modbus/RS485 Network I/O Modules
Enclosure Dimensions (4501-897)
TB4
DATAQ
RUN
ST
"T" RAIL DIN MOUNTING
DIN EN 50022, 35mm
(1
4. 18
68.9)
DFT
CL
0
1
2
3
46 45 44 OU
43 42 OU
41
TB OU RT OU
RT
T1
T0
4 T3 N T2
N
TB3
36 35 34 33 32 31
TB LR CO
3 TN M D D B A
DIGITAL OUTPUTS
RS485
PWR
3. (9
755.
3)
RTD INPUTS 0,1
TB IN0 IN0 IN0IN1 IN1IN1
1 + - L + - L
2. (5
349.
4)
RTD INPUTS 2,3
TB IN2 IN2IN2 IN3 IN3 IN3
2 + - L + - L
21 22 23 24 25 26
11 12 13 14 15 16
TB2
TB1
3.90
(99.1)
1.05
(26.7)
4.35
(110.5)
NOTE: ALL DIMENSION ARE IN INCHES (MILLIMETERS)
SERIES 934MB ENCLOSURE DIMENSIONS
4501-897A
Block Diagrams and Schematics
48
Model 932MB/934MB Modbus/RS485 Network I/O Modules
8. Accessories
Series DI-900MB Software Interface Package (Model 100969)
The Software Interface Package combines the DI-900MB Configuration Software, RS-232 to RS-485 Serial Converter, Interface Cable, and Instructions, into a complete kit for interfacing with Series DI-900MB I/O Modules.
DI-900MB Configuration & Control Software
Series DI-900MB modules are configured with this user-friendly Windows 95/98® or NT® Configuration Program.
Optionally, any software that supports the Modbus/RTU protocol may be used to configure and control Series DI900MB modules, but the use of this software makes getting started easier. All module functions are programmable
and downloadable to the modules via this software. The software also includes on-line help. Non-volatile memory
provides program and configuration storage within the module.
RS-232 to RS-485 Serial Adapter
This device is a non-isolated, port-powered, signal converter for communication between the RS-232 serial port of a
personal computer and the RS-485 network interface of Series DI-900MB I/O Modules. It is used in conjunction
with the DI-900MB Configuration Software for simple reconfiguration, testing, and troubleshooting of Series DI900MB I/O modules. As a port-powered device, it is not intended for driving fully loaded RS-485 networks over
long distances, and does not have sufficient power to drive terminated networks. The adapter has DB-9F connectors
at both ends and plugs directly into the common DB-9M serial port connector of most personal computers. The module is connected to the RS-485 side of this adapter via a separate interconnecting cable (see Interface Cable described
below).
Interface Cable
This 3-wire cable is used to connect the RS-485 side of the Serial Adapter to the RS-485 network terminals of Series
DI-900MB modules. This cable is 8 feet long and has a DE-9M connector on one end, and three stripped and tinned
wires on the other end. The wires are labeled A, B, and C for connection to the module D, Dbar, and COM terminals,
respectively.
Isolated Signal Converter (Models 100974 and 100975)
This unit provides an isolated interface between the host PC’s RS-232 port and RS-485 Modbus network devices.
Signal conversion is bidirectional with operation that is transparent to all devices. The RS-485 network supports up to
32 devices (including the Signal Converter) across 4000 foot distances. Installation of additional network devices or
extending the distance requires the Network Repeater described below. Optional 115V AC Power (Model 100974) or
230V AC Power (Model 100975). Power cord included. The Model Number 100976 connects the PC’s RS-232 port
to the Isolated Signal Converter.
Isolated Network Repeater (Models 100977 and 100978)
This unit isolates and boosts RS-485 signals to extend communication distances or increase the number of devices on
the network. Each Repeater permits the addition of a network branch with up to 32 devices (including the Network
Repeater) and will transmit RS-485 signals another 4000 feet. Operation is transparent to all devices and no handshaking is required. Two terminal blocks are provided for 120 ohm resistors to terminate both ends of the network
branch. Optional 115V AC Power (Model 100977) or 230V AC Power (Model 100978).
Accessories
49
DATAQ Instruments, Inc.
241 Springside Drive
Akron, Ohio 44333
Telephone: 330-668-1444
Fax: 330-666-5434
E-mail: [email protected]
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